Wikipedia:Featured article candidates/Heavy metals/archive2

The following is an archived discussion of a featured article nomination. Please do not modify it. Subsequent comments should be made on the article's talk page or in Wikipedia talk:Featured article candidates. No further edits should be made to this page.

The article was promoted by Ian Rose via FACBot (talk) 14:22, 22 October 2016 [1].

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Heavy metals

Nominator(s): Sandbh (talk) 01:59, 7 August 2016 (UTC)

This article surveys the field of heavy metal definitions; discuss their properties, origin and abundance; and sets out their many uses.

The first unsuccessful nomination (here), attracted commentary, support, opposition or contributions from User:R8R, User:Nergaal and User:Graeme Bartlett; and User:Nikkimaria provided an image review.

With subsequent considered help from User:YBG, I believe all outstanding issues have been addressed, and the article is the better for it. Sandbh (talk) 01:59, 7 August 2016 (UTC)

There has been a lot of work done, but I am surprised that we now have archive2, as I thought that the work to get it up to scratch never stopped from the archive1 point! Graeme Bartlett (talk) 02:15, 7 August 2016 (UTC)

Support by R8R

I gladly support the article and its promotion. If FAC1 failed but yielded this quality, it wasn't for nothing. (Note: I also reviewed the article during the first FAC, at which I was a little pickier as there were more problems to point at.) There article now reads very well and there's nothing I want to add.--R8R (talk) 18:48, 9 August 2016 (UTC)

I'll review the article. Note that I reviewed the article during the FAC1 and I eventually supported it after my concerns had been addressed. The article, however, has apparently continued to change since then, so I'll perform another review.--R8R (talk) 11:37, 7 August 2016 (UTC)

• "it was described" -- I think this falls under WP:WEASEL

  I moved the citation to show that the "it was described" comes from a properly attributed (and reliable) source.

• "The term later become associated" typo

  Fixed, and 10/10 for spotting that one.

From what I've read so far, the article is great. There's nothing I have questions against or (at the moment) find missing. Very, very well done. Note for self: take a look at FAC1 comments and see if they can provoke any further critical analysis.

Thank you!

• "Some heavy metals, especially chromium, arsenic, cadmium, mercury, lead and thallium are" should there be a comma after "thallium"? (you're the native speaker, of course; just asking)

  OMG we have our own article about this. MOS allows either style. I oppose the mandatory style, so will leave the comma out.

  Including the serial comma would give "Some heavy metals, especially Cr, As, Cd, Hg, Pb, and Tl are". I think what R8R is suggesting is instead "Some heavy metals, especially Cr, As, Cd, Hg, Pb and Tl, are": I think this is indeed better because it makes clear where the parenthetical listing of the heavy metals being discussed ends (although I can understand its omission – I kept forgetting it when writing Fe, because you tend to forget it for very long asides). Double sharp (talk) 06:36, 8 August 2016 (UTC)

  Ah, I see. I think it's looking OK now. Sandbh (talk) 09:10, 8 August 2016 (UTC)

• Speaking of the serial comma, that paragraph now contains two lists, one of which includes the comma and one doesn't ("lead and thallium", "tin, and antimony"). I know the comma is a separate issue and is not strongly bound to anything (engvar and so on), but uniformity must take place anyway.--R8R (talk) 16:09, 8 August 2016 (UTC)

  I believe I've checked and eliminated all serial commas apart from the ones needed to eliminate ambiguity and those in reference titles

• "Some heavy metals, especially chromium, arsenic, cadmium, mercury, lead and thallium are potentially hazardous due to the toxicity of some of their combined or elemental forms.[n 12] Hexavalent chromium, for example, is highly toxic as is mercury vapour and many mercury compounds.[54] These six elements have a strong affinity for sulfur" text flow is a little weak in that the third sentence mentions "the six elements" mentioned in the first sentence, and it would go much better if that sentence immediately followed the first one, or perhaps the second one was parenthesized or maybe even removed. (I wasn't being picky, this simply interrupted me reading the article.)

  I'll look closer at this one.

  Have made some adjustments to the first two sentences; see what you think. Sandbh (talk) 11:12, 8 August 2016 (UTC)

  Well done.--R8R (talk) 16:09, 8 August 2016 (UTC)

• As a general note, it's common for humans to first discuss ups and then downs, so I would swap Toxicity and Biological role

  Agree. Given the subject matter and that most people associate HM with toxicity I thought it would be better to list the information in a more natural way?

  Sure, as long as you're confident in your choice (as this is a tiny question that affects little to nothing).--R8R (talk) 16:09, 8 August 2016 (UTC)

• "(see next section)" also, you wouldn't have to refer to material as the reader would have already read it.

  Oh, I see. Let me have another look at this.

  I've left the order as toxicity, and then biological activity, so as to match the lead, which mentions toxicity before essentiality (as do all applicable definitions that I can recall). Sandbh (talk) 04:31, 9 August 2016 (UTC)

I have to take a break here and will continue as soon as possible.--R8R (talk) 12:35, 7 August 2016 (UTC)

• For fairness's sake, I'll say that apart from being toxic, permanganate has been sold in crystals in drugstores as a good antiseptic (not sure if you should react in any way)

  I can vaguely remember this was the case. Emsley suggests it's no longer available so I didn't say anything about this application.

  I see your point. Though I'll say it is very well-known among common people, at least those around me. (It was, however, outlawed in common drugstores five or less years ago after someone learned how to use it to make home-made drugs.)--R8R (talk) 16:09, 8 August 2016 (UTC)

• I was initially sceptical about the table, but good disclaimers around it make up for anything I was unsatisfied with.

  Yes, it caused me quite a bit of stress which is why it wasn't there the first time round.

  Normally, I would try to do that in a piece of readable text. Not saying your solution is worse or anything; just different.--R8R (talk) 16:09, 8 August 2016 (UTC)

• "platinum the most ubiquitous given it has been said to comprise 20% of all consumer goods" this bears some distrust. How come platinum, one of the rarest metals, is ubiquitous?

  Emsley says, "Indeed, this metal is involved in oil refining, car exhausts, fibre optic cable, computer hard disks, fertilizers, paints, jewellery, anti-cancer drugs, laboratory equipment, and pacemakers.

  I am still worried. Just in case, I checked a dictionary on the word "comprise" and I think the phrase should be reworded. Surely this can be worded in a way that doesn't raise my eyebrow.--R8R (talk) 16:09, 8 August 2016 (UTC)

  Thank you, I've edited this bit to make it clearer. Sandbh (talk) 04:31, 9 August 2016 (UTC)

  Thank you, much better.--R8R (talk) 18:47, 9 August 2016 (UTC)

In general, wow. This read like a perfect article and on the top of my head I can't think of any significant issue with that. I'll re-read the comments that came from the FAC1 and immediately after that and think once again. Right now, the article seems absolutely great to me. Maybe I'd reorder the sections, but that's about it.--R8R (talk) 13:37, 7 August 2016 (UTC)

Thank you very much for your gracious feedback. Sandbh (talk) 04:25, 8 August 2016 (UTC)

• "in question.[38] as at" one superfluous period

  Fixed. I owe you an eagle eyes award (and a non-English native, at that---I'm impressed). Sandbh (talk) 04:31, 9 August 2016 (UTC)

  I was carefully reading what I said I would review, no big deal. :) --R8R (talk) 18:47, 9 August 2016 (UTC)

Comments by Johnbod, leaning oppose

• I really don't like the title, which strongly implies, if not states, that there is a chemical element called "Heavy metal". Somewhere you need at least one "s"; there are various possibilities. Heavy metals (group of elements) might be one way. But it seems they are not all elements on some definitions?

Yes, I've had some on-again off-again reservations about the title. How about Heavy metal (science and engineering)?

• The lead is way too short. The first sentence isn't really a definition, or a scoping-out of the area within which the different definitions lie. At least the first para of the next section should probably be added, plus more of the article summarized. You can read all the existing lead & know only 3 examples. Roughly how many are there, on maximal and minimal definitions? As someone with very little knowledge of chemistry, the parts of the article I've read raise more questions than they answer. Try to imagine your reader is a not especially bright 16 year-old, at least at the top of the page.

OK I'll revisit the lead. I appreciate your input as a non-chemist. Sandbh (talk) 04:35, 8 August 2016 (UTC)

I've augmented and edited the lead. The first sentence is unchanged as it captures the nub of what a heavy metal is, and anything more specific wouldn't be representative (or would be too detailed). As you suggested, I added some words from the next section so as to give context to the "definition". There are now 16 examples of heavy metals, plus indicative lower and upper boundaries. There's also a paragraph about their properties. The only section the lead doesn't touch on is the Etymology and usage section which I suspect can be left to the main body of the article. How does it look now? Sandbh (talk) 09:04, 8 August 2016 (UTC)

I accept your comment re the lead section. When I intend to read the whole article, I often "cut to straight to the business" and skip the lead (which, of course, I shouldn't have done here). I just read the lead now, after you had added your comments and they had been responded to, and the lead does a fine job of introducing the concept to the reader. Maybe one thing we're missing is a pre-text template {{not to be confused with}}:

Not to be confused with Heavy metal (music).

I don't think this is necessary as the title of the article makes its scope reasonably clear. Sandbh (talk) 04:31, 9 August 2016 (UTC)

I won't insist; yet I'll note another wikilink is normally good as interlinks are good in general and make articles less alienated.--R8R (talk) 18:47, 9 August 2016 (UTC)

Note that is Heavy metal music in fact. Johnbod (talk) 15:19, 10 August 2016 (UTC)

Have added the template in light of R8R's reasoning. Sandbh (talk) 11:24, 11 August 2016 (UTC)

The lead is certainly much better now. There is still room for some more, and the sections: 5 Formation, abundance and occurrence, and 6 Properties compared with light metals, don't seem to be represented. I wondered if there is too much emphasis on the question of toxicity. Is " is often assumed to be toxic..." in the 1st sentence actually referenced anywhere? I'd be inclined to cut that. Surely, few think iron is toxic, but maybe many don't know it is a heavy metal. Johnbod (talk) 15:19, 10 August 2016 (UTC)

Thank you Johnbod. Section 5 is represented in the lead by, "Heavy metals are relatively scarce in the Earth's crust." In compressing this section down to nine words I was guided by MOS:LEAD where it says the lead serves as a summary of the articles most important contents. I personally find this section to be quite interesting, and it takes a while to explain the subject matter, but it's not that important, almost in the same way that section 2 (Etymology and usage) isn't that important, and hence is not mentioned in the lead. I can, however, say more about section 5 in the lead if you feel its importance warrants this.

Section 6 Properties compared with light metals, is summarised in paragraph 3 of the lead.

The reference to heavy metals being assumed to be toxic is taken from the widely cited paper by Duffus (2002) who says, "There is also a tendency to assume that all so-called “heavy metals” have highly toxic or ecotoxic properties. This immediately prejudices any discussion of the use of such metals, often without any real foundation." So in the lead I say that heavy metals are often assumed to be toxic. I haven't gone as far as Duffus by saying that such assumptions are often unfounded, because (a) I think that an "assumption" calls itself into question well enough; and (b) paragraph two of the lead gives a fair summary of the toxicity question (and only mentions iron as an essential heavy metal, after first discussing the more notable toxic metals, rather than saying anything about its toxicity). The only mention of the toxicity of iron, if it's taken in excess, occurs later in the article in the toxicity section. Does this see reasonable? Sandbh (talk) 12:31, 11 August 2016 (UTC)

But what else would I want here. Do you find that something is missing now? (As for the title, I won't judge. It seems to me that this is too minor a question to seriously discuss. If you think this is causing problems (not think this could cause problems for someone; for you), then let's just do it. Otherwise, you may be overthinking the problem. (we also have titles for other groups of elements in singular forms: alkali metal, group 4 element, noble gas, etc.)--R8R (talk) 16:09, 8 August 2016 (UTC)

If it was just Heavy metal, there would not be a problem (of that sort), but I'm not sure this can be claimed to be WP:PRIMARY. Heavy metal (chemistry) would be better than the present title (oddly, that redirects to Toxic heavy metal, which should surely be fixed!), or I think "Heavy metal (science and engineering)". Johnbod (talk) 15:19, 10 August 2016 (UTC)

HM (Chemistry) now redirects to Heavy metal (chemical elements). Sandbh (talk) 03:26, 12 August 2016 (UTC)

• Wow! I really don't agree with the previous reviewer. But then he's a chemist.

Johnbod (talk) 17:55, 7 August 2016 (UTC)

For the record, I am not a chemist. Though I've been writing articles in Wiki for five years or so and am pretty familiar with this now.--R8R (talk) 16:09, 8 August 2016 (UTC)

Ok, apologies! You had me fooled anyway. Johnbod (talk) 15:19, 10 August 2016 (UTC)

• I'll start this point again, as the above has got lengthy. I'm still not keen on the first sentence "A heavy metal is generally defined as a metal with a relatively high density, atomic weight or atomic number, and is often assumed to be toxic." - that is to say including the part after the comma in it. It reads oddly, and means that your opening definition essentially breaks down to two statements: a) "I can't exactly say what a HM is", and b) "you might think they are toxic (but you're wrong)". This is unsettling for the reader, especially if they had no assumptions about toxicity, which will often be the case. It would be better to move "often assumed to be toxic" to the start of the next para - I still can't see that this wrong assumption is a sufficiently fundamental point to include in the initial definition. People expect the opening sentence to provide a clear and concise definition, and while it may be inevitable here that the first part is unable to do this, the additional confusion the 2nd part introduces seems unnecessary.

I've relocated the toxicity assumption from the end of the 1st sentence to the start of the 2nd as you suggested. Sandbh (talk) 01:47, 14 August 2016 (UTC)

• Still (mostly) on the lead, the article does not include, or stress, key points to enable non-chemists to understand the subject. Take the following statement:

"All native metals are (generally agreed to be) heavy metals."

- is this true? More importantly, why don't I know if it is true or not after reading the article?. If it is true, I'd urge you to put something like it in the lead. If it is not, at least explain/qualify/discuss it lower down. It's a pity the term native metal is not generally known to non-chemists, and other more familiar terms such as precious metal and base metal should be brought in, or references to metals suitable to metalworking. As far as I can tell from reading the article, a working layman's definition of what a heavy metal is might be "all the substances you think of as metal, plus another bunch you've never or hardly ever heard of, but which might be used in tiny quantities in making your pc, mobile phone etc." I ought to be clearer on this after reading the article, but I'm not.

I can't find the statement, "All native metals are (generally agreed to be) heavy metals." anywhere in the article. Sandbh (talk) 01:47, 14 August 2016 (UTC)

No, THAT'S MY POINT!! It should be there, if true. If not true, say why not. Johnbod (talk) 03:29, 14 August 2016 (UTC)

I've removed the reference to native metals---more trouble than it's worth. Sandbh (talk) 06:04, 14 August 2016 (UTC)

• "The high densities of native metals such as copper, iron and gold may have been noticed in prehistory." This is a rather ridiculous statement, given the massive metalworking industries that dominated later periods of prehistory, in Eurasia anyway. I've no idea what your reference says, but we can be entirely sure they were "noticed".

Johnbod (talk) 18:15, 13 August 2016 (UTC)

This sentence now reads, "The advent of metalworking, at the end of the stone age, may owe its origin (in part) to the observation of the high densities of native metals such as copper, iron and gold." I hope more clearly conveys the intended meaning. Sandbh (talk) 01:47, 14 August 2016 (UTC)

No, that's worse. Johnbod (talk) 03:29, 14 August 2016 (UTC)

How about this: "Awareness of the high densities of naturally occurring heavy metals such as gold, copper and iron may have contributed to the advent of metalworking, and the end of the Stone Age.

No, that's also terrible. People did not go to the vast trouble of metalworking to make dense objects. It's very clear from the archaeological record what they were doing. They wanted strong tools with sharp blades, from base metals, or beautiful and long-lasting jewellery from precious metals, and in making these materials that could be melted and cast in moulds, or softened and hammered, or worked in other ways, were very helpful. Equally, they could hardly fail to be aware of the density, but that was incidental. Metal was far too valuable to use for weights (looms, fishing nets), where stones or sometimes ceramics were used (this is pretty much true long after prehistory, until the Early Modern period). Note how very rare prehistoric use of lead is, until they needed it for plumbing. Maces are made with stone until historic periods.

Oh dear, I didn't intend to give the impression that early metalworking revolved around attempts to make heavy objects. I was trying to say that, in prehistory, the heaviness of native metals may have served to distinguish them from other objects in the environment. The rest of the section then continues the theme: thousands of years of all known metals being relatively dense; the shock discovery of light metals in 1809; and Gmelin's subsequent distinction between light and heavy metals. Anyway I've renamed the section to Terminology as per your suggestion, and edited it to try and make my intent clearer. Sandbh (talk) 02:33, 20 August 2016 (UTC)

• The more I look at this article, the less happy I am. I don't know much about most aspects of the subject, but the bits I can judge easily are not done well. I understand the subject lacks a clear definition, which causes problems. It seems to me that the important things one can usefully say to explain the subject to non-chemists should begin with saying that all the "historical" metalworking metals, both base and precious, are HMs. At the moment I can't even work out from the article whether this is actually true, and I really should be able to. With the exception of aluminium (already noted), all the metals commonly encountered as the main component materials of everyday objects are also all HMs - or are they? I don't know from the article, and I should.

I've added a hopefully helpful hatnote to the article explaining which elements, for the purposes of making the article easier to follow, are presumed to be HM. I thought about saying something about this in the article proper but the content seems more appropriate/efficient as a hatnote. There is now a paragraph in the lead picking up on your suggestion re base and precious metals. I didn't use the term base metal given its multiple definitions. Re all domestic metals being HMs. The end of the lead says HM are present in many [i.e. not all] aspects of modern life, and gives several examples. In this light I don't understand the need to say that all the metals commonly encountered in everyday objects are not HM. Sandbh (talk) 10:29, 20 August 2016 (UTC)

Johnbod, the hatnote is gone, now incorporated into the lead and main body of the article, further to the comments from Vanamonde and edwininlondon, below. Sandbh (talk) 11:17, 23 August 2016 (UTC)

• "Etymology and usage" - actually nothing is said about the etymology of "heavy metal" (probably nothing needs to be said). The only info as to first use is pretty weaselish - does nobody know in what language and when it was first used? Incidentally, I can't find the term at all in the original OED (under "heavy") - perhaps I missed it. I'd change the title to "Terminology" maybe, and try to establish the origin properly.

Gmelin's density-based use of the term heavy metal in 1817 (and its corollary light metal) is the earliest I've been able to find. To this day it's the most popular of the more specific definitions. The earliest quote in the OED dates to only 1864: "Jrnl. Chem. Soc. XVII. 126 In support of the view that thallium is one of the heavy metals, the following reasons may be given." [see the OED entry for "heavy", a.¹ (n.)] Worse still, Duffus's widely cited International Union of Pure and Applied Chemistry (IUPAC) paper was only able to trace scientific use of the term back to 1936. Since low density metals were only discovered from 1809 onwards I doubt the heavy metal/light metals distinction, as a science-based concept, would have an origin predating these times.

In the context of the above I think it's reasonable to say, "An early use of the term "heavy metal" dates from 1817, when the German chemist Leopold Gmelin divided the elements into nonmetals, light metals and heavy metals." Certainly, it's better than relying on Duffus' 1936 assertion or trying to do something with the OED.

I like your suggestion to change the section title to Terminology. I just need to square away your earlier comments about pre-historical awareness of metals as dense substances. Sandbh (talk) 13:48, 19 August 2016 (UTC)

• The first paragraph of this section seems very important, and needs expansion, even its own section. Unfortunately it currently begins very badly with the prehistory bit, which I discuss above.

This paragraph may be better now, following the changes discussed above. Sandbh (talk) 10:29, 20 August 2016 (UTC)

• The first periodic table image needs a caption explaining it better - perhaps quite a long one, or specific explanation in the text.

A caption is possibly not now required, given the new hatnote at the top of the article. Sandbh (talk) 10:29, 20 August 2016 (UTC)

• "Formation, abundance and occurrence" - out of my comfort zone, but seems ok. Somewhere something should be said about how the less common ones are extracted/processed. Numbers of the other heavy metals are presumably rare and very expensive; it would be good to say something about this.

Done. Sandbh (talk) 08:04, 4 September 2016 (UTC)

• "Uses" This is the section that really worries me. It mostly reads like a random selection of snippets off the internet. The density section has a long para all about sports! The "Strength-based" one is one far-too-long para, the start of which is very wide-ranging (and much better in itself) but it is wholly unreferenced until the toys, which won't do at FAC, however basic the statements. More below.

I'm not sure what is surprising about the sports paragraph—the examples given seem clear enough. It's a bit longer due to the mini-story at the end about hammer throw hammers. The strength paragraph has now been split into smaller paragraphs. I've added citations to the uses examples. I would've liked to have fewer citations however the literature on these kinds of very specific uses of heavy metals is scattered. Sandbh (talk) 05:57, 21 August 2016 (UTC)

• what is lead doing in the "Strength-based" section? Is it especially strong in alloys? Since it isn't in pure form, this should perhaps be explained.

I've changed the section title to "Strength- or durability-based" to make it clearer (much clearer, I hope) why metals such as lead are included here. This is also elaborated in the paragraph.

• "Home electrical systems, for the most part, are wired with copper wire for its good conducting properties." - well, nobody is arguing with that, but it hardly does justice to the role of HMs as electrical conductors, and for long the only practical ones. Gold and silver as specialized conductors should be mentioned.

Silver and gold are now mentioned. Sandbh (talk) 13:12, 20 August 2016 (UTC)

• There is never any attempt at explaining in chemical terms why HMs are the most suitable for their uses - for example in the "Nuclear" section. Surely plenty could be said here? There's just lists of uses, and it is where these are familiar (density and strength in particular) that they seem randomly collected. Which makes me worry about the unfamiliar bits.

Done. Sandbh (talk) 04:26, 8 September 2016 (UTC)

• I think, since the definitions are so variable, some sort of complete list of HMs should be given. That, plus a definition, is probably what people are looking for in such an article, not stuff about weights in sports, and I think they may have to be given it. There are various ways to arrange it. One might start with the ones everybody agrees about, and work outwards in groups. I suppose this information can be extracted, with some difficulty, via the periodic table diagrams, but few non-chemists can work with these.

The definition issue has hopefully now been clarified; I'll see if I can address the "complete" list as part of edwininlondon's comments, below, along the same lines. Sandbh (talk) 22:35, 25 August 2016 (UTC)

Johnbod (talk) 14:00, 18 August 2016 (UTC)

I'm hoping that the hatnote I've discussed above has addressed your last dot point. Sandbh (talk) 11:17, 20 August 2016 (UTC)

Thanks - I've read your responses, but I'm away at the moment & will assess changes & respond mid-week. Johnbod (talk) 15:27, 20 August 2016 (UTC)

Thank you Johnbod. There are three o/s dot points I'll see if I can tackle before then. Sandbh (talk) 23:54, 20 August 2016 (UTC)

Support by Nergaal

• There could be some nitpicking done,but the article looks much, much better than the last time. Also, I suggest having the title styled as "HM (chemistry)". Nergaal (talk) 18:06, 11 August 2016 (UTC)

  Thank you Nergaal. Before I saw your post I changed the title to "Heavy metal (chemical elements)" as I thought that would capture the subject matter and have the least amount of anchoring to any field. Sandbh (talk) 23:44, 11 August 2016 (UTC)

  • Are there other "XXX (chemical element)" articles? Plus, when a biologist or physicist refers to HM he implies chemistry. Anyways, I think no parenthesis at all is the best. The disambig page can jsut have (disambiguation) in the title. Nergaal (talk) 10:36, 12 August 2016 (UTC)

    There are no other "XXX (chemical element)" articles that I could find. I agree that a biologist would be implying chemistry; I'm not sure that a physicist would, nor would a metallurgist, astronomer, mechanical or electronic engineer—the latter four would at least be implying chemical elements (maybe also alloys, at least for the metallurgist). For that reason I'd be reluctant to call it "HM (chemistry)" whereas the current title captures the subject of the article quite nicely. What did you mean by your last sentence(?)—I didn't understand it. Sandbh (talk) 05:02, 13 August 2016 (UTC)

    Much as I am somewhat loath to admit it, I daresay the musical genre has a pretty good claim to be the main topic as well, so I think both need disambiguations. Although I would point out that the parenthesised text is meant as disambiguation, and Nergaal's suggestion "heavy metal (chemistry)" works perfectly well and is as concise as it could possibly be. Even though they are important in other fields, are they not defined by being chemical elements? Double sharp (talk) 15:28, 13 August 2016 (UTC)

    • My suggestion in fact. I still think it preferable. Johnbod (talk) 18:17, 13 August 2016 (UTC)

I'll change it to HM (chemistry). I may need some admim help to tidy up things. Sandbh (talk) 01:47, 14 August 2016 (UTC)

I think I'll say a word as well. I don't think "(chemistry)" is a right specification. The article currently mentions three main criteria, and "heavy metals" can be defined with any of the three: density, atomic mass/number, and chemical behavior. Only the latter can unambiguously be shown as related to chemistry, but neither atomic numbers nor density are. The fact metals are chemical elements is best shown by the current "(chemical elements)" specification.--R8R (talk) 15:22, 14 August 2016 (UTC)

How do you feel about "Heavy metal (science and engineering)"? Sandbh (talk) 02:11, 15 August 2016 (UTC)

Heavy metal isn't really a term relevant to engineering, I'd have thought. But it's unclear to me why density and atomic mass/number are not "related to chemistry". Johnbod (talk) 02:20, 15 August 2016 (UTC)

Sandbh well explained why density isn't as closely related to chemistry as to engineering. My first idea was that the science closest to the density aspect was materials science, but that's pretty close to engineering as well. As for atomic numbers, these definitions are usually used in the context of nuclear reactions (radioactive decay or nucleosynthesis), which is covered by nuclear physics rather than chemistry.--R8R (talk) 12:48, 16 August 2016 (UTC)

I was trying to at least cater for some of the density based applications of heavy metals such as to provide ballast in, for example, racing cars, planes and ships. This has more to do with engineering than chemistry. Sandbh (talk) 07:27, 15 August 2016 (UTC)

"Heavy metal (science and technology)" might work too, as something broader. Sandbh (talk),

Both "Heavy metal (science and engineering)" and "Heavy metal (science and technology)" are great. Certainly better than the current "Singular (plural)" title. Perhaps I would choose the one with "technology," though, of course, "Heavy metal (science and engineering)" is also fine.--R8R (talk) 12:48, 16 August 2016 (UTC)

I've changed the damned title to Heavy metal (science and technology). Sandbh (talk) 06:14, 18 August 2016 (UTC)

Comments by Vanamonde

This is an interesting read, well done. I have not previously participated at an FAC, so I think I'm going to limit myself to leaving comments, and not actually support or oppose (unless I find exceptional reason to). Here's some comments to begin with. Vanamonde (talk) 07:08, 21 August 2016 (UTC)

Thank you very much for your comments.

My apologies for my comments coming all over the article: this is partly because I'm new at FAC, and partly because the article itself has undergone so many changes. Anyhow, here's a few more suggestions. Vanamonde (talk) 17:17, 28 August 2016 (UTC)

Lede

• Is the hatnote above the article necessary? Surely it could be incorporated into the lead, and make the article aesthetically more pleasing that way?

Done. Yes, I agree and have merged the hatnote into the lead, and adjusted the definitions section. I was feeling the same way myself. Sandbh (talk) 03:48, 22 August 2016 (UTC)

• Okay that's a lot better, but I don't think you need the "sometimes" in the "sometimes quoted as..." "quoted" does not imply "universally." in my mind, at least.

"Is quoted" sounds too authoritative. Given Duffus describes heavy metal as an effectively meaningless term I think the "sometimes" qualifier strikes the right tone. Sandbh (talk) 11:31, 23 August 2016 (UTC)

Definitions

• "In metallurgy, for example, a heavy metal may be defined on the basis of density,[5] whereas in physics the distinguishing criterion might be atomic number,[6] while a chemist would likely be more more concerned with chemical behaviour.[7]" This seems a rather over-qualified statement, does it not? Why not "In Metallurgy, a heavy metal is defined..." etc.

I'd like to do that but there is no consistency within these disciplines. For example, in metallurgy heavy metals are sometimes referred to in terms of their high atomic numbers, and in chemistry in terms of their densities. Sandbh (talk) 03:48, 22 August 2016 (UTC)

• Is there at least evidence to go with "In metallurgy, heavy metals are frequently defined on the basis of...

No, there isn't  :( Sandbh (talk) 11:39, 23 August 2016 (UTC)

• "in 2002 it was described..." by whom, and in what context?

Done. Sandbh (talk) 06:36, 22 August 2016 (UTC)

• "chemical behaviour or periodic table position are known or have been used" perhaps better as the simpler "have historically been used." or some such.

Done. Sandbh (talk) 07:57, 22 August 2016 (UTC)

• "definitional looseness"; better as "uncertainty over definitions?

Partly done. Changed to "uncertainty around definitions" Sandbh (talk) 03:48, 22 August 2016 (UTC)

• "Atomic weight definitions have been expressed as, for example, greater than sodium (22.98); or greater than 40;[n 4] or 200 or more." this is an awkward construction, IMO. How about something like "Definitions based on atomic weight can range from elements heavier than Sodium (atomic weight 22.98); or greater than 40" etc.

Done. I hope the new version is better. Sandbh (talk) 00:53, 24 August 2016 (UTC)

• The next sentence is somewhat contradictory with this one.

Yes, there is not necessarily any consistency in the literature when it comes to density, atomic weight and atomic number definitions. Sandbh (talk) 00:53, 24 August 2016 (UTC)

• In that case, I might incorporate what is now footnote three into the text. It is fairly relevant, after all.

Done. Sandbh (talk) 01:20, 31 August 2016 (UTC)

• the test described as "metallic impurities that are colored by sulfide ion" is not very clear. Surely it does not mean that an element is a heavy metal if impurities caused by said metal also contain sulfide? But that is what it reads as.

Done. Edited to make meaning clearer. Sandbh (talk) 00:34, 24 August 2016 (UTC)

• " the latter figure is 3.6 times that of lead (at 11.35 g/cm3)." Hardly controversial, but still should have a citation.

Done. Sandbh (talk) 01:20, 31 August 2016 (UTC)

• "and the term metalloid later acquired a completely unrelated meaning." There's no source at the end of this sentence. Does it need to be duplicated from someplace?

Done. I don't know what I was thinking when I wrote that. Sandbh (talk) 04:18, 29 August 2016 (UTC)

• "The heaviness (and malleability)" might be better as "The weight and malleability". I know that "weight" has a technical meaning slightly different from its colloquial usage, but I think it still works in this context: "heaviness" sounds really odd.

Done. Sandbh (talk) 04:18, 29 August 2016 (UTC)

• Wondering if the very last paragraph of the "definitions" can be appended to the third-to-last paragraph. The material just seems a little scattered at present, and I'm thinking of ways to tighten it. Not sure this would work, but it's a thought.

Done. It was a good thought. See how the section looks now. I did have to bust out the origins and use of term subsection into its own section, but I think this is justified. The two sections now seem tighter and more interesting to me. I'll have to add a few citations about element 118, which I'll do shortly. Sandbh (talk) 08:24, 29 August 2016 (UTC)

• Still a rather clunky title, but better. Let me see if I can think of a better one.

OK. Sandbh (talk) 01:20, 31 August 2016 (UTC)

Terminology

• The "terminology" section seems not very distinct, content-wise, from the previous section. Could the two be merged, with perhaps a sub-section being created for "history of terminology" or something like that?

This section was originally called Etymology and usage but I changed in light of Johnbod's comment. How would you feel if I changed back to that title and made it a subsection of the prior section, as per your suggestion? Sandbh (talk) 10:17, 22 August 2016 (UTC)

• I would indeed prefer that.

Done. But I changed the title to "History of the term and usage" in light of Johnbod's previous comments about Etymology. Sandbh (talk) 22:35, 23 August 2016 (UTC)

Biological role

• Personally, I would prefer the "biological role" section to come prior to the "toxicity" section. In my mind, at least, it makes more sense to understand what the role of a metal is under normal circumstances, before learning what happens when things go wrong (broadly speaking).

Ordinarily I'd agree. In this case I put toxicology before biology in light of the strong association of toxicity with "heavy metals". Does that seem reasonable? Sandbh (talk) 10:17, 22 August 2016 (UTC)

Done. Sandbh (talk) 10:38, 23 August 2016 (UTC)

Toxicity

• I think the subsections of the "toxicity" section could do with a little bit of expansion. I understand that the section is merely a summary of a full article, but it seems a little brief. The "heavy metals of concern," for instance, could at least mention the different ways in which those metals are toxic.

Done. At last. Sandbh (talk) 01:45, 3 September 2016 (UTC)

• Similarly, the rest of the section says that something is toxic several times, without mentioning why or how. We don't need too much detail here; but just as you've mentioned DNA damage for V2O5, it seems appropriate to mention the outcome for Germanium, Indium, and so forth.

Done. Ditto. {rechecking of sources to follow, in the background) Sandbh (talk) 01:45, 3 September 2016 (UTC)

• There is no source for the toxicity of copper sulfate (or is it the emsley source? In which case, I would duplicate it, as they are superficially disconnected statements).

Done. Sandbh (talk) 03:48, 22 August 2016 (UTC)

• "insoluble uranium compounds, radiation aside, are poisonous" This is an odd construction. perhaps something like "insoluble Uranium compounds are poisonous to [insert target here], in addition to the dangerous radiation they emit."

Partly done: I left out mention of a target. I think it is safe to say that something is poisonous, and only clarifying this if "targets" other than people were intended. Sandbh (talk) 03:48, 22 August 2016 (UTC)

• "Heavy metals can cause environmental problems" this is rather vague. Could you be more specific?

Done. Edited to make the meaning clearer. Sandbh (talk) 11:27, 22 August 2016 (UTC)

• Wondering if we can find a better sub-section title than "heavy metals of concern." If they're toxic, surely they are all of concern?

Done. I've added a short contextual paragraph to the start of this section, and beefed up the subsection title so that it's now called "Heavy metals of particular concern." Does that help? Sandbh (talk) 12:43, 29 August 2016 (UTC)

• Just wondering if Minamata disease deserves a mention in the last subsection: it's a highly notable example, after all. Entirely up to you, though, I'm sure there's a number of such examples.

Done. A highly notable example, as you said. Sandbh (talk) 13:30, 29 August 2016 (UTC)

Formation, etc

• "Heavy metals up to the vicinity of iron" might not be very clear to a non-chemist; perhaps add "in the periodic table" so that folks know what you mean.

Done. Sandbh (talk) 13:28, 30 August 2016 (UTC)

• "Stars lose much of their mass when it is ejected late in their stellar lifetimes, and sometimes post-ejection as a result of a neutron star merger,[79][n 18] thereby increasing the abundance of elements heavier than helium in the interstellar medium." This sentence is rather confusing (and, I believe, ungrammatical) as it stands. Could you please clarify it?

Done? Sandbh (talk) 13:28, 30 August 2016 (UTC)

• Much better.

• "They constitute" should not be the opening line of a paragraph, though. Likewise for the nest para.

Fixed.

• Excellent work on that figure: but I'm wondering why Technetium, Polonium, and some of the Lanthanides and Actinides are missing from it.

Thank you. The missing "ghost" elements have abundances much less than one part per trillion. In discussing the composition of the figure with another editor, and looking at some similar figures in the literature, we concluded that they were not worth showing. This was explained at the end of the figure, in note 14. Since this note was a bit out of the way I've merged it into note 13, right next to the table title. Sandbh (talk) 04:18, 29 August 2016 (UTC)

• That should do it. One last followup: I wonder if there's an easy way to format the numbers that label periods and groups, so that they look different from the elements they are next to?

I've bolded the period and group numbers. I'm not sure I like it but let me see if can get used to it. Sandbh (talk) 04:42, 31 August 2016 (UTC)

I much prefer this; it's a lot more readable.

• "Rather, they are largely synthesised by neutron capture" I might add the clarifying phrase "from elements with a lower atomic number" after this, for clarity.

Done. Sandbh (talk) 13:28, 30 August 2016 (UTC)

• Why does the slow process stop at Bismuth?

Done. Sandbh (talk) 13:28, 30 August 2016 (UTC)

Nicely done.

• "as the most noble of metals" I know that "noble" is linked, but I still think you should clarify the usage there with "noble, or corrosion resistant" or something like that.

Done. Sandbh (talk) 04:22, 30 August 2016 (UTC)

• The paragraph beginning "Stars lose..." is not tied in to the rest very well. I'm not sure how to fix it, because I'm not certain of the intent. Are you trying to describe how heavy metals get from stars to planets? If so, it should be made clearer.

Done. It should be tied in better now. Sandbh (talk) 12:26, 30 August 2016 (UTC)

• Similarly, the last paragraph is also rather disconnected at present; trying to think of a good way to shuffle the content to make it flow better...

The three paragraphs before the last paragraph talk about the occurrence of HM in the crust. I though it would be OK to finish the section with a few words on the situation below the crust. The penultimate paragraph, with its discussion of siderophiles, presages this. Sandbh (talk) 10:46, 30 August 2016 (UTC)

• "From a whole of Earth perspective, some other..." ungrammatical, and not entirely clear. Why should affinity change depending on whether you look at the whole earth? The same comment could be applied to the note as well.

Fixed, I hope. Reworded to try and make things clearer. Does it read better now? Sandbh (talk) 10:29, 30 August 2016 (UTC)

• Still a bit confused, tbh: the linked articles suggest siderophiles are those that sink to the core: how, then, can you only assess that for the crust?

OK, if you're still a bit confused then this bit needs some more work. Siderophiles tend to be concentrated in the metallic core. In the crust they're mostly found in chalcophile ores, with the exception of gold which mainly occurs in native form. I've edited this paragraph some more. How does it seem now? Sandbh (talk) 03:33, 31 August 2016 (UTC)

Ah yes this is better. final quibble, I hope: this fragment "but only at the whole of Earth level" is clunky and ungrammatical, could you do something with it?

Done. I hope. Sandbh (talk) 06:28, 3 September 2016 (UTC)

• As it's currently phrased, the last sentence of the section could be parsed to mean that the heat generated drives the magnetic field. This is obviously not the intent, so wondering if you could rephrase.

Done. Qualification and note added. Sandbh (talk) 04:22, 30 August 2016 (UTC)

Properties

• The "more reactive" entry for light metals has no source

Done. Thank you. Sandbh (talk) 07:28, 30 August 2016 (UTC)

• "Lithophile" links to an article which I don't think is the article you want...

Done. Thank you.

• You need to clarify what the sulfides and hydroxides are soluble or insoluble in, I think: or is it assumed to be water? I'm not enough of a chemist to know whether this is a serious issue.

Not done. For a chemist and most science professionals this would not be an issue since water is the standard solute for conducting "wet" chemistry, as opposed to "dry" chemistry e.g. when gunpowder explodes. I presume a more general reader would interpret "soluble" to mean soluble in water, unless otherwise indicated. For example, the definition of soluble given by the Oxford Dictionary is, "(Of a substance) able to be dissolved, especially in water". Sandbh (talk) 04:54, 30 August 2016 (UTC)

• Okay.

Uses

• "platinum the most ubiquitous given it has been said to be found in, or used to produce, 20% of all consumer goods." This sounds complicated, and is not quite grammatical. How about making it a separate sentence, and then replacing "it has been said to be" with "that it has been"?

Fixed. Split into two sentences. I can't say, "given that is has been" since even Emsley only goes as far as saying, "It has been said that…". Sandbh (talk) 23:36, 30 August 2016 (UTC)

• "Density-based" is an odd section title: though slightly redundant, might "density-based uses" be better?

Fixed. I changed it to "Weight- or density-based" which I think may be easier on the brain. Sandbh (talk) 23:36, 30 August 2016 (UTC)

• The first sentence of "density based" hangs by itself without a source. While I would agree that it is an acceptable summarizing sentence, I would prefer it being merged with the paragraph below.

Done. Against my better judgement (I think) but let me mull on it for a while. Sandbh (talk) 23:36, 30 August 2016 (UTC)

• "sink rate" is a rather jargon-ish term

Fixed. Sandbh (talk) 23:36, 30 August 2016 (UTC)

• "in situations requiring maximum weight in minimum space (for example in watch movements)" This fragment is confusing: you start the sentence discussing its use in ballast, and then say this stuff about minimum weight: but surely metals are not used as ballast is watches? I'd suggest simply breaking it up into separate sentences.

Fixed. I rearranged the wording so that ballast used are mentioned first. Sandbh (talk) 01:45, 3 September 2016 (UTC)

• I'd hardly describe military artefacts as being a part of "everyday life." wondering if you can just break the military uses into another sentence, which would also avoid the rather odd use of "civilian".

Fixed. Trimmed the ref to everyday life.Sandbh (talk) 01:45, 3 September 2016 (UTC)

• I don't think the "respectively" works in the sentence "as are (for example) nickel, copper, indium and cobalt in, respectively, white, red, blue, purple, green and black gold." might it not be easier simply to link "colored gold" and omit the "respectively?"

Done. I'll miss the purty colours. Sandbh (talk) 01:45, 3 September 2016 (UTC)

• "chemical production (bismuth)," chemical production seems rather general: wondering if you could make is specific, or break it into its own sentence.

Done. Sandbh (talk)

• I wonder if Catalytic_converter#Construction could be worked into this anywhere, possibly in the "palladium" fragment, possibly elsewhere. It was considered a notable example when I studied chemistry, and I'm sure it still is.

Done. Nice. Sandbh (talk) 02:17, 3 September 2016 (UTC)

• Do correct me if I'm wrong, but my recollection is that the colored compounds and complexes that allow metals to be used as coloring agents are a property of partially filled d-orbitals, which would mean most transition metals. Is it still true for Uranium?

You're right. It's also the case for actinides such as uranium. See the table called Approximate colors of actinide ions in aqueous solution, at the end of the properties section in the actinide article. Sandbh (talk) 02:17, 3 September 2016 (UTC)

• Also, I think it might be worth explaining the chemical mechanism (electrons that get excited at the appropriate energy levels) here, because that is both interesting in and of itself, and also explains how they can be used to give color in so many different ways (in flame, in solution, etc).

Not done (kind of). There's an outstanding item raised by Johnbod along the same lines re why heavy metals are most suited for their uses. When I fix that one, I'll incorporate your good suggestion into it. Sandbh (talk) 06:38, 3 September 2016 (UTC)

• Is the entire first chunk of Electronics etc sourced to ref 181? (which is fine, just checking)

Fixed. Thank you. Sandbh (talk) 05:57, 3 September 2016 (UTC)

• Another paragraph beginning "They have been used..."

Fixed. Sandbh (talk) 02:31, 3 September 2016 (UTC)

• I wonder if "permanent magnets" would be a useful link to have.

Done. Sandbh (talk) 02:31, 3 September 2016 (UTC)

• "Nuclear shadowing" is a redlink, so I'm wondering if a brief phrase of explanation would be appropriate.

Fixed. Sandbh (talk) 03:43, 3 September 2016 (UTC)

• "In nuclear science, accelerated nuclei" the use of "accelerated" is rather odd here, and almost superfluous, I think.

Done. Sandbh (talk) 02:31, 3 September 2016 (UTC)

Okay, I think that's all I've got. Good job with the article. As I mentioned when I started the review, I'm relatively new at FAC, so I'm not going to go "support" or "oppose": I've let my comments, nearly all of them have been acted upon, and the coords can judge for themselves what that contributes to consensus. Regards, Vanamonde (talk) 08:19, 2 September 2016 (UTC)

Comments by edwininlondon

Interesting topic and it generally reads well. A few comments just to get started. More later. One thing that strikes me as missing, given all the different criteria, is a table that shows which ones are indisputably heavy, which ones are heavy in metallurgy in its least strict definition (density > 3.5 gr per cm3), etc. That would visually show 2 things: which elements we're talking about and the variation in definition.

Thank you very much for your comments. The table at the start of the Definitions section shows metals and metalloids according to their density. The middle five colour categories cover those having a density of 3.5 gr per cm3 or more. Sandbh (talk) 13:07, 22 August 2016 (UTC)

I guess what I meant was that the article doesn't tell me which elements are indisputably heavy, no matter which criterion used. Actually spelling out the names of the elements. Followed by a list of elements that are sometimes called heavy. Right now the reader has to do a lot of work to figure this out.

There are no metals that are indisputably regarded as heavy metals. With careful wording, this is perhaps the best that could be done:

(1) list mercury, thallium, lead, bismuth, radium, actinium, thorium, protactinium and uranium as being likely to meet most definitions;

(2) list the 70 other metals counted as heavy metals in this article, including polonium and astatine;

(3) list the dozen other metals also regarded as HM by some definitions.

Would that help? Sandbh (talk) 12:53, 23 August 2016 (UTC)

Yes. Including the statement that no element is considered HM unanimously.

Done. Sandbh (talk) 01:12, 28 August 2016 (UTC)

Other comments:

• I like the new title Heavy metal (chemistry) much ore than the old ones

Sorry, the title is now HM (Science and technology) following the discussion in the Nergaal comments subsection, above. How does this look? Sandbh (talk) 13:07, 22 August 2016 (UTC)

Much better

• density in the lead should be linked. Yes, there are many links already, and normally wouldn't need a link, but when placed next to atomic weight and number, it should I think. Likewise, metallurgy, periodic table, and all of the elements mentioned. If this results in a sea of blue, then de-link things like mining, lead-based paint and golf clubs. A user who lands here is more in need to get to a page of an element quickly.

Done. Sandbh (talk) 13:07, 22 August 2016 (UTC)

• The caption of the tungsten image is too long. Stick to the essentials

Done. I deleted the etymology bit. Hopefully only the essentials are left. Sandbh (talk) 12:12, 22 August 2016 (UTC)

• All metals known up to 1807 --> This is not a well known set, so I'd rephrase it. Something along the lines of "The metals that first were discovered were all heavy: iron, ... In 1807 the first light metal was discovered, ..., followed by ... Later discovered heavy metals include ... By the way, the year 1807 only appears in the lead.

Done. Sandbh (talk) 13:07, 22 August 2016 (UTC)

• In 2002 it was described[8] --> any particular reason why the [8] isn't at the end of the sentence?

Fixed. Old habits etc. Sandbh (talk) 13:07, 22 August 2016 (UTC)

• Quantitative criteria used to define heavy metals have included density, atomic weight and atomic number. --> feels repeating previous paragraph

Fixed. Sandbh (talk) 11:09, 23 August 2016 (UTC)

• are mainly the heavier transition and post-transition metals _-> do we end up with a circular definition here? Biochemstry's definition of heavy is class B. Class B are mainly the heavier transition and post transition metals.

I don't think so? Or are you saying that "heavier transition and post transition metals" tells someone no more than "Class B" does?

Yes, you've just changed one thing I've never heard of with another.

This sentence now reads, "…all the metals in periodic table columns 3 to 16 that are in row 4 or greater, in other words, the transition metals and post-transition metals." Does the reference to periodic table columns and rows make it clearer, given the periodic table at the start of the section? Oh, and I'm now worried about terms like lanthanides and actinides and, in the preceding paragraph, s- and f-block metals. Sandbh (talk) 05:46, 25 August 2016 (UTC)

• the term "heavy metal" --> inconsistency with "the name heavy metal"  : italics or quotes?

Done. Thank you. Sandbh (talk) 13:07, 22 August 2016 (UTC)

• do scientific literature and vernacular really need to be linked? there is so much blue already and these 2 add little

Done. Sandbh (talk) 13:07, 22 August 2016 (UTC)

More later. Edwininlondon (talk) 16:25, 21 August 2016 (UTC)

• Heavy metals essential for life (see next section) --> consider swapping the Toxic and Biological role sections, so we don't need this awkward forward reference.

Done. In response to multiple requests. Sandbh (talk) 10:35, 23 August 2016 (UTC)

• selenium (antioxidant functioning and hormone production). --> Looks like a source is missing. I looked at [53] which is the first reference, but that doesn't have a page number.

Done. But see next dot point. Sandbh (talk) 11:40, 25 August 2016 (UTC)

• bacteria for metabolic processes.[38][52][55] --> adding 3 references seems unnecessary. One should suffice

Provisionally done. I rearranged the paragraph up to this point, and trimmed a couple of references, to facilate paragraph bundling. This is provisional response because Emsley currently has no page numbers, as discussed in my response at the end of this thread. Sandbh (talk) 11:40, 25 August 2016 (UTC)

• The purple permanganate ion MnO–4 is toxic. Ingesting .. body --> source missing

Done. Sandbh (talk) 11:45, 25 August 2016 (UTC)

• Heavy metals can degrade air, ... paints; treated woods --> source(s) missing

Done. Sandbh (talk) 22:20, 25 August 2016 (UTC)

• There seems to be quite a few statements in the Formation, abundance and occurrence section without source. I don't have the sources that are mentioned, but missing for instance seem to be: via stellar nucleosynthesis, would consume rather than release energy., being the s-process and the r-process, faster than nuclei can decay, thereby increasing the abundance of ,

Done. These statements are largely derived from Cox's book on the elements, their origin, abundance and distribution, as cited. He discuses nucleosynthesis in stars at some length, pp. 73 to 89, especially. I don't normally cite each sentence in a paragraph, if they are all sourced from the same reference. I place the source at the end of the last applicable sentence. I did however add another cite from Cox re "would consume, rather than release energy", as I missed a few of the applicable pages in the other Cox citation. Sandbh (talk) 12:54, 24 August 2016 (UTC)

• non-metals or nonmetals?

Fixed. Sandbh (talk) 01:44, 24 August 2016 (UTC)

• as lithophiles or chalcophiles. Lithophile (rock-loving) --> I'd explain it right away: as lithophiles (rock-loving) or chalcophiles (ore-loving). Lithophile ..

Done. Good. Sandbh (talk) 01:44, 24 August 2016 (UTC)

• reference [86] has 3 sources, Sanders 2003; Preuss 2011; Wohlers & Wood 2015, but none have page numbers to indicate the exact place. One with precise reference would be better

Partly done. The first two references are university media releases on the web, hence readily accessible but having no page numbers, discussing different aspects of the subject matter. The last one is a journal article which I have now deleted. Sandbh (talk) 23:56, 25 August 2016 (UTC)

• tensile strength --> wikilink

Not done. It's linked in the immediately following table, along with hardness, and it would look a bit odd to remove the links from the table. Sandbh (talk) 01:44, 24 August 2016 (UTC)

I always link first use in lead, in body, and in table, since tables are likely to be consumed separately by scanning users. But we all have our own style.

I like your approach and will adopt it. Sandbh (talk) 00:33, 25 August 2016 (UTC)

Done. Sandbh (talk) 04:15, 9 September 2016 (UTC)

• While it is relatively easy to distinguish .. colourless complexes). --> needs sources

Done. Sandbh (talk) 03:06, 26 August 2016 (UTC)

• In underwater diving, .. in handicap horse racing .. of competitors. --> needs sources

Done. Sandbh (talk) 05:13, 26 August 2016 (UTC)

• In the quote "The higher the projectile density, the more effectively it can penetrate heavy armor plate ... Os, Ir, Pt and Re ... are expensive ... U" --> making the elemnts links makes it easier for the reader who doesn't know these elements by abbreviation

Done. Good idea. Sandbh (talk) 01:44, 24 August 2016 (UTC)

• and armour piercing projectiles --> needs a source

Done. Sandbh (talk) 13:24, 25 August 2016 (UTC)

• coinage and jewellery. --> source

Done. Sandbh (talk) 22:20, 25 August 2016 (UTC)

• of either zinc carbonate; tin oxide; or --> the semicolons look odd here, why not commas?

Fixed. Sandbh (talk) 21:30, 25 August 2016 (UTC)

• They have been used in batteries.. button cell batteries. --> needs a source

Done. Sandbh (talk) 05:34, 26 August 2016 (UTC)

• [155] (using lead, bismuth, thorium or uranium in the latter case). --> should the reference not come at the end?

Done. Sandbh (talk) 01:44, 24 August 2016 (UTC)

• Note 9 Google recorded 945 citations for the paper in question[37] as at 19 April 2016. --> A link to the Google Scholar results page would count as a source

Not done. I tried getting rid of the note and turning it into a non-date specific linked source to Google Scholar but the result looked awkward: one citation after "frequently cited"; another one after "proposal". As well, nothing is gained by a link to the Google Scolar search results page beyond what is already conveyed by the current note. Well, at least I hope I interpreted your comment right. Sandbh (talk) 10:27, 24 August 2016 (UTC)

I'm just looking at it from a point of being an easy to verify claim.

Right, I'll keep the note and add a link to the Google Scholar page. Sandbh (talk) 00:33, 25 August 2016 (UTC)

Done. Sandbh (talk) 05:21, 25 August 2016 (UTC)

• Whether or not element 118, the heaviest in the noble gas group, is a metal remains to be seen. --> source?

Oh, the sentence to which this note is attached says, "Elements from atomic number 104 (rutherfordium) onwards are sometimes called superheavy metals" and cites Loveland (2014). Since nobody knows for sure where 118 will be on the metal--nonmetal spectrum, and I haven't been able to find any decent (i.e. relativistic) predictions addressing this question, I think the Loveland citation needs to have a qualifying note pointing out that E118 may or may not be a metal (and hence may or may not be a superheavy metal). As an editorial caveat there is no source. Sandbh (talk) 02:49, 24 August 2016 (UTC)

I'd rather see sources attached to a statement about the uncertainty being a metal or not. To be an FA it has to adhere to the highest standards, not much room for editorial caveats.

If I include a university web link showing 118 as a non-metal, and a Royal Society of Chemistry weblink showing it as a metal, thereby illustrating confusion as to the status of 118, would that work? While the Loveland-sourced statement is fine at face value, I feel a duty of care to raise an eyebrow wrt 118. Sandbh (talk) 00:33, 25 August 2016 (UTC)

• Note 15 source?

Done. Sandbh (talk) 07:47, 24 August 2016 (UTC)

• Note 18 source?

Done. Sandbh (talk) 07:56, 24 August 2016 (UTC)

• Note 21 source?

Not done. This one is an cautionary editorial note concerning how the uses section was organized. As such it has no source. Sandbh (talk) 07:47, 24 August 2016 (UTC)

• I'll do a spot check of references later, but i can see already quite a few that have no page or page range. For instance, Emsley 2011 is used many times, without page references but is a 700 page. Check all others for page numbers.

My standard practice is to give precise page numbers, unless the whole reference e.g. a journal article is relevant [Addendum: or if the reference has no page numbers e.g. it's on the web; or if it's very short]. Emsley is organised alphabetically by element and each entry is organised the same way so is easy to look up. I have used him as a major source and I didn't want to add a whole lot more unnecessary citation clutter. Sandbh (talk) 01:44, 24 August 2016 (UTC)

I think being easy to verify is more important than citation clutter, besides there are ways to reduce citation clutter. Same with the whole journal article making the point: it is likely to be in the abstract then, so why not give the abstract's page number? Take Duffus 2002. Referenced 5 times. But [b] is really specifically covered on page 798, not the whole article. These are just examples. For me to meet FA criteria the referencing overall needs to be better.

This is fine be me; aside from Emsley, I'd expect there wouldn't be too many sources without page numbers so I'll look again at these. Noting my approach to Emsley, would you be looking for page numbers for him, too? Sandbh (talk) 00:33, 25 August 2016 (UTC)

Definitely. Edwininlondon (talk) 20:47, 25 August 2016 (UTC)

Edwininlondon (talk) 20:22, 24 August 2016 (UTC)

Done. Sandbh (talk) 07:17, 10 September 2016 (UTC)

Celebration time
Only three two of your items still to address (list of HM's; wikilinks in lead-body-tables; absent page nos). Sandbh (talk) 05:34, 26 August 2016 (UTC)

Great. I've made some changes to the references, but leave it for you to decide and act upon this:

• inconsistent ISBN format: some are ISBN 10, others 13. Choose 1. You can convert with this tool: http://www.isbn.org/ISBN_converter (I didn't know this either but was asked to do so when I did my FAC nomination.)

Done. Sandbh (talk) 05:11, 8 September 2016 (UTC)

I will check some sources next. Edwininlondon (talk) 18:01, 26 August 2016 (UTC)

Summary of outstanding items

There are only a few things I still need to address:

Johnbod

• how less common HM are extracted/processed and say something about the HM that are rare and very expensive
• why HM are most suited for their uses
  • • The article has been greatly improved while at FAC. Actually, I still find "The weight (and malleability) of naturally occurring heavy metals such as gold, copper, and iron may have been noticed in prehistory and led to the first attempts to craft metal trinkets, tools, and weapons." very irritating - poorly worded and misleading - can the source really support that? Better to just drop it, & move the link to "naturally occurring" elsewhere. The paragraph lengths could do with some adjusting. Some are much too long, and others rather short. You're using US English, no? If so "artefact" needs changing. Johnbod (talk) 13:50, 22 September 2016 (UTC)

G'day Johnbod, long time no hear.

The source says:

It seems unlikely that we will ever know where or when metals were first used deliberately; but it is possible to speculate about how early man first became aware of metals as a particular class of substances. In all probability it was a gradual process, incidental to his continuing use of other materials. To begin with, it may have been simply the observation that some stones or pebbles behaved differently from others, in that they seemed 'heavier', did not crack or chip when hammered, and in some cases could be beaten into any desired shape. <New paragraph> Such would have been examples of the so-called 'native' metals -- that is, metals not combined with other elements in mineral ores but existing in more or less pure state, lying about on the ground or exposed in mineral outcrops. Those most obvious to early man would have been gold, copper and iron; platinum and silver also occur as native metals, but much more rarely.

I've done some paragraph adjusting. There are still a few below 50 words and a couple marginally above 200 but I don't see a succession of very short ones, nor are there any very long ones (for me that's more than 300 words). I hope it's OK now.

No to US English; the article's written in Australian English. Sandbh (talk) 05:06, 23 September 2016 (UTC)

Usually such passages include melting/glowing when fires were accidentally lit over nuggets. "Trinkets" is ridiculous language, wholly unjustified by the source, and you still imply that weight was significant in a way I don't think the source intends. Johnbod (talk) 04:59, 7 October 2016 (UTC)

Hello again Johnbod. Yes, the source discusses smelting on the following page. On the page before the passage in question the source uses the word "trinkets" in reference to the earliest known human-made metal items. The chapter in which the source mentions these two points, and discusses heaviness (and malleability) as a possible impetus for the first use of metals, is called From stone to copper the contextual significance of which seems plain.

Here are more supporting extracts from the source, including the two paragraphs I quoted previously re heaviness:

The only older man-made articles ever found are four copper pins or awls from Cayonu…and a few small copper trinkets [underline added] from Iran, including a pierced pendant…

*****

Once the particular properties of metals and their ores began to be recognised they must have become important trade goods…and this raises the question of what it was that led man to begin using metals in the first place. Almost certainly, it was not the compulsion to make better tools or weapons. That imperative would only have produced more improved techniques of working flint and obsidian, in the tradition of millions of years of tool making.

Cyril Stanley Smith, Professor Emeritus at...MIT and a renowned authority on metallurgical history, has pointed out that 'necessity is not the mother of invention—only of improvement. A man desperately in search of a weapon or food is in no mood for discovery; he can only exploit what is already known to exist. Innovation and discovery require aesthetically motivated curiosity; they do not arise under pressure of need, although of course once new properties of matter become known they are available for any use.'

All the evidence we have of early metallurgy supports this opinion. Because of the unusual character and initial rarity of metals, they were first used for decoration rather than utility, for ornaments rather than knives. Their wider use had to await the emergence of receptive and economically advanced societies which were able to grasp and exploit the potential of metals. (p. 8)

*****

It seems unlikely that we will ever know where or when metals were first used deliberately; but it is possible to speculate about how early man first became aware of metals as a particular class of substances. In all probability it was a gradual process, incidental to his continuing use of other materials. To begin with, it may have been simply the observation that some stones or pebbles behaved differently from others, in that they seemed 'heavier', did not crack or chip when hammered, and in some cases could be beaten into any desired shape.

Such would have been examples of the so-called 'native' metals—that is, metals not combined with other elements in mineral ores but existing in more or less pure state, lying about on the ground or exposed in mineral outcrops. Those most obvious to early man would have been gold, copper and iron; platinum and silver also occur as native metals, but much more rarely. (p. 9)

*****

There were, to begin with, no obvious paths to follow from native metals to smelting. (p. 10)

Sandbh (talk)

I've edited the opening sentence of the Origins and use of the term section so as to place more emphasis on native metal malleability. Sandbh (talk) 00:51, 8 October 2016 (UTC)

That's an improvement, but trinkets is still a very silly word to use. It is defined as " 1. a small ornament, piece of jewelry, etc., usually of little value., 2. anything of trivial value.", whereas all the indications we have as to the status of very early metal objects is that they were rare and understandably highly valued. There is no reason not to use the accurate and non-pejorative "jewellery", and avoid your source's misguided informal vocabulary. It's pity you haven't used more and better sources here. Johnbod (talk) 17:15, 11 October 2016 (UTC)

I'd question the need for more and better sources. The coverage and pedigree of the source appears to speak for itself.

The author notes that they drew on a world-wide collection of materials on the history of metals, physical evidence, and archaeological sites compiled by Willard C. Lacey, a practising mining geologist before becoming Professor of Geological and Mining Engineering at the University of Arizona, and later Professor of Geology at James Cook University in Townsville, Queensland.

The manuscript for the source was read by a panel of academics and scientists including: Judy Birmingham, Senior Lecturer in Archaeology, University of Sydney; Professor Geoffrey Blainey, Dean of the Faculty of Arts, University of Melbourne; Christopher Davey, Senior Lecturer in Mineral Engineering, Royal Melbourne Institute of Technology; Professor Ted Ringwood, Director of the Research School of Earth Sciences, Australian National University; and Doctor Howard Worner, former Professor of Metallurgy, University of Melbourne.

On the use of the word "trinkets", other sources use similar language such as "trinket metallurgy", "trinket technology", and "copper age trinkets".

While "trinkets" may be an accurate descriptive word from a modern perspective I agree that it can have a misleading connotation, as you have explained. "Jewellery" also seems to be a less than suitable term to refer to the earliest decorative metal objects given its common association with gems. For these reasons I've deleted "trinkets" as I think "ornaments", which is already in the same sentence, says enough (and is appropriately descriptive and objective). Sandbh (talk) 08:58, 13 October 2016 (UTC)

edwinlondon

• wikilinks in the lead-body-tables
• pages numbers for citations lacking them (mainly Emsley)

--- Sandbh (talk) 06:53, 3 September 2016 (UTC)

All outstanding items have been addressed. Sandbh (talk) 07:20, 10 September 2016 (UTC)

• I'm still not happy with the lead. The reader should be told there is no single element called heavy by all criteria.

Done. Mercury, lead and bismuth are in the spotlight.

• The first periodic table doesn't work for me either. The reader expects to be able to see which elements are heavy, but can't. The caption should at least help.

Done. Yes, I hope its heat map successor hits the mark.

• Why is there no periodic table for definition by atomic number and by chemical behaviour? This will help visually convey the whole point of messy definition.

Done. There are now.

• Source check: I'm not sure where the data for the first table comes from (e.g., where I can see that Vanadium has density between 5 and 6.9). Can you enlighten me?

Done. Citations and refs added.

• Otherwise all 7 spot checks I did checked out fine.

Thank you. Sandbh (talk) 06:45, 11 September 2016 (UTC)

Edwininlondon (talk) 17:59, 10 September 2016 (UTC)

PS: There is a little bit of work I need to do in the background, including checking that my new i's and t's are dotted and crossed. Sandbh (talk) 06:45, 11 September 2016 (UTC)

Done. Sandbh (talk) 00:51, 13 September 2016 (UTC)

@Edwininlondon: Did you have any other concerns? Sandbh (talk) 12:16, 22 September 2016 (UTC)

Support from me. Much improved in last 2 months. Edwininlondon (talk) 19:03, 6 October 2016 (UTC)

Support and comments from Jim

I have a degree in chemistry and i wouldn't think of tackling such a large and difficult topic, brave effort. I think the earlier reviewers have made a good fist of improving it, just a couple of comments, more to show I've read it than anything else.

Thank you Jimfbleak.

circuit inks in circuit boards, first "circuit" looks redundant

Fixed.

I may be wrong, but it's my understanding that references should end with a full stop (easy enough to search/replace if you accept that

All references now end with full stops. Sandbh (talk) 23:39, 26 September 2016 (UTC)

Good luck Jimfbleak (talk) 13:22, 26 September 2016 (UTC)

Coord notes

• Several images added or changed since the last FAC so we'll need a new image review.

@Nikkimaria: would you be able assist please? Thank you, Sandbh (talk) 22:25, 8 October 2016 (UTC)

• You have a harv error at FN61 that suggests the citation doesn't correctly point to a reference -- this script highlights such errors.

Yes, I noticed this bogus error some time ago. The citation is correctly pointed to a reference. I suspect the "error" arises because the ref name is called up in the main body of the article, but is named earlier in the article in a footnote. NFA required from what I can see. I'll ask Ucucha to have a look at their script. Sandbh (talk) 22:52, 8 October 2016 (UTC)

• You also have several duplinks so pls check if they're really necessary -- this script highlights the duplicates.

Thank you Ian. This was discussed under edwininlondon's comments. This editor advised that they "always link first use in lead, in body, and in table, since tables are likely to be consumed separately by scanning users." I though this was reasonable and adopted that practice. I've been checking to see that the article is consistent with this policy. I'll check it again. Sandbh (talk) 22:32, 8 October 2016 (UTC)

Done. I found and removed two redundant duplinks. Sandbh (talk) 10:38, 9 October 2016 (UTC)

Cheers, Ian Rose (talk) 22:13, 8 October 2016 (UTC)

Image review

• Suggest scaling up the X-ray tube image slightly so the labels can be easily read

Done. Sandbh (talk) 08:16, 9 October 2016 (UTC)

• File:Osmium_crystals.jpg: confused by the licensing terms here, as they seem to contradict each other - the first would not allow derivative works (and therefore would not allow the image to be used on Wikipedia), but the second and third tag would. This applies also to File:Chromium_crystals_and_1cm3_cube.jpg, File:Cadmium-crystal_bar.jpg, File:Lead_electrolytic_and_1cm3_cube.jpg

Hmm, despite the apparently contradictory licensing terms all four images were been pictures of the day which I presume means they were regarded as freely licensed? Sandbh (talk) 08:37, 9 October 2016 (UTC)

• File:Fertilizer.jpg: this appears to be a reproduction of a 2D label, which would mean the originating company (or their designer) and not the uploader would be the copyright holder. Nikkimaria (talk) 22:36, 8 October 2016 (UTC)

Relaced with an image of cerium(IV) oxide. Sandbh (talk) 10:17, 9 October 2016 (UTC)

Hi @Nikkimaria: how do you see my comments against point 2 above re pics of the day, and will the cerium(IV) oxide image pass muster? Thank you, Sandbh (talk) 10:38, 9 October 2016 (UTC)

Re point 2, it doesn't appear that the licensing issue was discussed in the featured picture candidacy of any of those images. The other image is fine. Nikkimaria (talk) 13:41, 9 October 2016 (UTC)

I guess if an image has three licenses then another user could use that image under the conditions of any one of those licences, which would mean these images should be fine. I'll see if there's a forum somewhere that I could ask for a review of this question. Sandbh (talk) 22:06, 9 October 2016 (UTC)

Have asked the question here (at the Media copyright questions page). Sandbh (talk) 22:43, 9 October 2016 (UTC)

• I rather liked File:Fertilizer.jpg. It says "Trace Elements" and all those element symbols are a nice touch. Any chance of contacting the manufacturer and getting permission? YBG (talk) 14:23, 9 October 2016 (UTC)

Yes, I'll contact the manufacturer about this. Sandbh (talk) 22:06, 9 October 2016 (UTC)

This could take a while however, so in the meantime I'll retain the cerium oxide image for FAC purposes. Sandbh (talk) 08:20, 10 October 2016 (UTC)

• About File:Osmium crystals.jpg and the other pictures of the day, the same file can be licensed under as many licenses as the copyright holder wishes and only one of them (but at least one must) has to be free - see commons:Commons:Licensing#Multi-licensing. The additional non-free CC-BY-NC-ND tag simply means that people can reuse the image under that license as well (if they are reusing it in a non-free collage, for example), it doesn't make a difference for us. Jo-Jo Eumerus (talk, contributions) 06:05, 10 October 2016 (UTC)

Thank you Jo-Jo. 08:29, 10 October 2016 (UTC)

@Ian Rose: G'day Ian. With the above advice from Jo-Jo Eumerus I believe all the items listed in your Coord notes have now been addressed. Sandbh (talk) 08:29, 10 October 2016 (UTC)

N

The article looks much better.

Thanks Nergaal. Sandbh (talk) 10:58, 16 October 2016 (UTC)

• I am just a bit puzzled by the heat diagram image. I think N 1 needs to be expanded to explicitly list the 10 criteria. My thought is to have a second column in the caption with 10 bullet points: density; atomic weight; atomic number; chemical behaviour; US Pharmacopeia; ?9?; biochemical classification. Also, maybe merge 0-1, split 8-9, and change the 2-3 from blue to something like a darkish gray. (Also, you think having * as green and ** as yellow in the table would help?)

Partly done. I've reworded the first paragraph of text under the heat map, and added a note spelling out, in condensed form, what the ten criteria are. I haven't merged 0-1, or split 8-9 as I don't see any advantage in doing so. I haven't changed 2-3 blue to darkish gray as I don't see the point; the blue-green-yellow-orange-red sequence looks fine to me. I think having * as green and ** as yellow would make them harder to read. Sandbh (talk) 10:58, 16 October 2016 (UTC)

My thought process was that the difference between K and Na is pretty irrelevant to this article, but maybe 8/9 might be more interesting. As for the blue, I personally don't like it because it stands out and gives the impression that say Rb is pretty HM, when in fact it passes at most 3/10 of the criteria. Nergaal (talk) 08:25, 17 October 2016 (UTC)

Done. I merged 1 and 2–3 into 1–3; and I broke out 8–9 into 8, and 9. I tried replacing the blue with a darker grey, but with the new colour categories all the dark grey boxes shouted out the rest of the table. I think the blue—it's actually pale cyan—is OK now. Sandbh (talk) 05:08, 19 October 2016 (UTC)

I looked at the change, and it seems that there were changes other than the splitting/merging mentioned. I counted the colors (before and after) and they match the totals, but the totals indicate that something else was done, no double unintentionally.

before edit	categories counts	8-9 18		6-7 50		4-5 16		2-3 5		1 3	0 4	nm 19
change		+3		-6		+3		+1			-1	=
after edit	counts categories	5 9	16 8	44 6-7		19 4-5		9 1-3			3 0	19 nm

Here's where I think the problems may lie:

Before	After	Elements
6–7	9	Cu, Cd, Sn
6–7	4–5	Ge, Se, Te
8–9	6–7	Hf, Ta, W, Re, Os
0	1–3	Mg

YBG (talk) 07:57, 19 October 2016 (UTC)

Thank you YBG. These changes were what I had in mind when the edit summary said, in part, "correct [fix] heat map". Either I had the colour wrong on the chart, or in my own papers. I've now checked the colour category allocations twice and will do so again tomorrow. Sandbh (talk) 11:44, 19 October 2016 (UTC)

Great! YBG (talk) 23:46, 19 October 2016 (UTC)

Done. Checked again, definition by definition, element by element, made some final corrections and adjustments. Note the mixed shading among the lanthanides as they go below and above a density of 7 gm/cm³. See also the near-perfect symmetry of the numbers of elements in each of the HM colour categories. Sandbh (talk) 10:58, 20 October 2016 (UTC)

And here's a summary of all the changes. I fixed one total (55→56)

old categories		8-9		6-7		4-5		2-3		1	0	nm
before edits	counts	18		50		16		5		3	4	19
changes	1st edit 2nd edit cumulative	+3 -2 +1		-6 +12 +6		+3 -5 -2		+1 -5 -4			-1 = -1	= = =
after edits	after 1st edit after 2nd edit	5 5	16 14	44 56		19 14		9 4			3 3	19 19
new categories		9	8	6-7		4-5		1-3			0	nm

YBG (talk) 08:03, 21 October 2016 (UTC)

Thank you, that looks good. Sandbh (talk) 11:41, 21 October 2016 (UTC)

• Also, I still don't know what you mean by " class B and borderline metals" and since this is redlinked it is a big problem. Do you mean Pearson's hard/soft classification?

Fixed. I added a note explaining the connection. Sandbh (talk) 00:48, 16 October 2016 (UTC)

What is the difference between the biochemical A/B separation and Pearson's HSAB theory. Nergaal (talk) 08:19, 17 October 2016 (UTC)

They're each derived from the work of Ahrland et al. (1958) but whereas Pearson treats Ti to Mn, Fe(III), Ga, As, and In as hard, Nieboer and Richardson say they're borderline; Bi is borderline v class B; Cd is soft v borderline. Nieboer and Richardson comment on Pearson:

Two different terminologies have arisen for this classification. We follow the original terminology of Ahrland et al. (1958) for reasons detailed elsewhere (Williams & Hale, 1966). In this convention, metal ions are separated into class A, class B and borderline. Pearson (1963, 1968a,b, 1969), while adhering to the general principles developed by Ahrland et al. (1958), refers to class A metal ions as 'hard acids' and class B metal ions as 'soft acids'. A number of recent chemistry texts (e.g. Huheey, 1978, pp. 276-88) include an account of these concepts, usually under the title 'hard and soft acids and bases'. However, such considerations are restricted to inorganic reaction systems and the implications for biological systems are not treated. Similar limitations apply to recent bioinorganic texts which provide information on these ideas (Angelici, 1975; Ochiai, 1977, pp. 56-7).

Nieboer E. & Richardson D. H. S. 1980, "The replacement of the nondescript term 'heavy metals' by a biologically and chemically significant classification of metal ions", Environmental Pollution Series B, Chemical and Physical, vol. 1, no. 1, pp. 3–26 (5–6), doi:10.1016/0143-148X(80)90017-8.

Sandbh (talk) 06:22, 19 October 2016 (UTC)

• The "An average 70 kg " sentence should be expanded to say that about 5g, most of the 1% is iron. I don't recall how much the others add up, but I almost suggest having a stacked bar diagram on the right would help since there aren't that many in Composition_of_the_human_body#Elemental_composition_list.

Done. I didn't take up your almost suggestion of a stacked bar diagram given the large number (52) of heavy metals in the human body, aside from the three now mentioned in the sentence in question (Fe, Zn, Pb). Sandbh (talk) 09:43, 16 October 2016 (UTC)

Abundance_of_the_chemical_elements#Abundance_of_elements_in_the_Universe has bars like I was thinking (no need to show numbers though). And Mineral_(nutrient) lists like 10 of them. IMO only the essential/useful HM should be listed, while the remaining ~40 that-exist-without-a-function should be ignored. Speaking of which, why is there so much lead? Just unintended ingestion? Nergaal (talk) 08:19, 17 October 2016 (UTC)

Done. All the essential HM are listed in the table, either individually or in the note referring to the other 45 heavy metals. Pb has a note re its relatively high occurrence. Sandbh (talk) 04:39, 18 October 2016 (UTC)

• Since lead is one of the most notable element with the "HM" label attributed to it, I think you could mention, lead paint and leaded gas. One very interesting factoid that I do actually think it can me mentioned is a study noticing that banning of leaded fuel was observed to lead to drop in violent crimes 20 years later - your call.

Done. Paragraph added to the Toxicity/environmental HM section. (Lead based paint is already mentioned in the lead; paint as a source of HM is already mentioned in the Exposure sources section). Sandbh (talk) 02:53, 16 October 2016 (UTC)

Nergaal (talk) 15:12, 11 October 2016 (UTC)

• Closing note: This candidate has been promoted, but there may be a delay in bot processing of the close. Please see WP:FAC/ar, and leave the {{featured article candidates}} template in place on the talk page until the bot goes through. Ian Rose (talk) 14:22, 22 October 2016 (UTC)

The above discussion is preserved as an archive. Please do not modify it. No further edits should be made to this page.