Talk:Nonmetal

RfC on discovery of the 23 nonmetals

Should this content on the discovery of the 23 nonmetals be removed from the nonmetal article? Sandbh (talk) 12:39, 23 July 2024 (UTC)

Considerations
1. WP:FAC criteria: Criterion 1b states that an FAC article is, "comprehensive: it neglects no major facts or details and places the subject in context".

2. Encyclopedic relevance: Content about the discovery of nonmetals has been part of the article since 2015. Throughout nine FAC nominations, there have been no objections or comments about its inclusion. After nearly a decade, it is unlikely that such content has suddenly become non-notable. Removing such information could be seen as knowledge censorship, which contradicts Wikipedia's principles.

3. Historical context: WP is an encyclopedia which means that it represents an organised compilation of collected facts. Given the subject matter of the nonmetal article, it follows that information about the discovery of the nonmetals is relevant. Indeed, there would be nothing to write about nonmetals but for their discovery. This includes the discovery of He off-planet; P as by-product of attempting to create the fabled philosopher's stone; and the discovery of F which killed some chemists along the way. These are notable items in the consolidated history of the discovery of nonmetals.

4. Discovery dates: The section is organised into two subsections:

• Nonmetals discovered before the concept chemical elements and nonmetals.
  
• Nonmetals discovered after these concepts were established.

This organisation provides clarity and context, showing the evolution of understanding regarding nonmetals.

5. Discovery methods: The discovery dates are accompanied by the methods used, where known. This is significant as it highlights patterns, such as:

• noble gases primarily extracted from air;
• halogens discovered via their halides;
• the variegated unclassified nonmetals via equally variegated methods; and
• nonmetals sometimes called metalloids via thermal extraction.

Expecting the general reader to piece together this knowledge from 23 separate articles is impractical and non-encyclopedic. This section consolidates important information for easier comprehension.

6. List-like content: The content of the section is to some degree list-like, as can be found in sections of numerous Wikipedia articles.

!Votes
Oppose removal. --- As RfC initiator. Sandbh (talk) 12:39, 23 July 2024 (UTC)

Remove. A key point has previously been made by @Johnjbarton in a prior section #Discovery, to repeat it:

The section in History called "Discovery" isn't about the discovery of "nonmetal". As the immediately following section makes clear, the concept of "nonmetal" dates from the late 1700s. In my opinion this section should be deleted. Johnjbarton (talk) 22:08, 26 June 2024 (UTC)

There is a further discussion in #"Discovery of applicable elements" article section where a second point is made:

@Sandbh You know I do not agree. You have gone over and over this. I am not convinced and I don't see anyone else being convinced. Factoids about elements before the concept of nonmetal elements or even the concept of chemical elements was invented is off topic and distracts the reader from the core concept. Johnjbarton (talk) 14:51, 20 July 2024

I supported the deletion then, and still do now. It really is not relevant what was in the article many years ago, Wikipedia is dynamic and evolves. There is already a significant article Discovery of chemical elements, this page should focus on the nonmetallic elements and off-topic factoids need to be removed or heavily edited. Ldm1954 (talk) 14:38, 23 July 2024 (UTC)

Remove Off-topic fluff. Johnjbarton (talk) 15:22, 23 July 2024 (UTC)

Remove per Ldm1954. This is not about the history of the classification "nonmetal". Though I might agree to a hatnote pointing readers interested in the discoveries of the individual elements to Discovery of chemical elements. Double sharp (talk) 17:48, 23 July 2024 (UTC)

Include as discovery of the included elements is significant to the topic. The discovery section also shows the diverse methods of production and identification of nonmetals. Graeme Bartlett (talk)

• Remove. Off-topic. Xxanthippe (talk) 22:38, 24 July 2024 (UTC).
• Remove, this is just the discovery of individual elements, there's nothing there that's intrinsic to them being non-metals. Headbomb {t · c · p · b} 04:08, 25 July 2024 (UTC)

Retain. The argument for removal is unconvincing; it appears to be based on the idea that this article should include only information about "the concept of nonmetal" and that any data about individual members of this small class seem to be pejoratively termed "fluff" and "factoids".

The long-standing inclusion of this information is germane in that it establishes a long-standing wp:consensus. While consensus can change; this happens through a discussion that results in a new consensus. The bold/revert/discuss strategy is a proven method for resolving such issues without edit warring.

Throughout this discussion, @Sandbh has made multiple attempts to tweak the presentation to meet the concerns raised, but the deletionists seem to remain uncompromisingly fixed that this information has no place in this article.

If no new consensus arises through this RfC, the long established consensus stands. If a new consensus arises, I encourage @Sandbh to find a new home for this information: either a new article or a new section in Discovery of chemical elements YBG (talk) 20:32, 25 July 2024 (UTC)

@YBG Sorry, but I disagree with your characterization of my role in this discussion. As I have previous discussed in one of the many times this content was discussed, I am not against including some discussion of the elements that informed the historical efforts leading to the creation of the category "nonmetal elements". That is what we need. I did not and do not claim that "any data about individual" nonmetal elements is fluff. But this is not what we are discussing. This is not a few sentences placed in the context of the article content. This is not even a WP:SUMMARY paragraph. It is a long section with ancillary footnotes. It detracts from the article mission.

@Sandbh has repackaged this material and reinserted it even after multiple editors objected. The same arguments then ensued. I have proposed a compromise that was ignored. My terse "fluff" comment on this RFC derives from my frustration at the unending discussions with zero progress.

The concept that existence creates a consensus is no where to be found in WP:consensus. This idea was made up. There is no consensus to include this material.

I agree that this material may indeed be suitable in an article like discovery of chemical elements. One of my previous points was that this article is part of a bigger picture like a chapter in a book. The entire contents of the book does not need to be jammed in here. Johnjbarton (talk) 21:03, 25 July 2024 (UTC)

@Johnjbarton Thank you for clarifying. I misunderstood you as I did not understand how this objection would not equally apply to other "fluff" or "factoids" about individual elements.

I agree, existence does not imply consensus. But WP:CONSENSUS at WP:EDITCON says Wikipedia consensus usually occurs implicitly. An edit has presumed consensus until it is disputed or reverted. Years of editing and multiple GA/FA reviews without this objection IMO constitute an implicit consensus. New editors have objected, so a formal RfC consensus is sought. If no RfC consensus arises, the previous implicit consensus stands.

— YBG (talk) 22:36, 25 July 2024 (UTC)

I just read the comments from the last two FAR. I do not think that they provide a general consensus for what is in the article, in fact the statement that the article contains too many factoids has history. Interestingly the point about band gaps (which @Sandbh has objected to) goes back to Oct 2023 for certain. Ldm1954 (talk) 00:51, 26 July 2024 (UTC)

WP:SILENCE is the weakest form of consensus. And right now, a clear majority is for removal. Headbomb {t · c · p · b} 22:19, 26 July 2024 (UTC)

@Headbomb I wholeheartedly agree. My point is that it is a form of consensus, and can only be overturned by a stronger form. Not sure a consensus is established simply by a majority of WP:!VOTEs.

In any event, what I see developing here is not actually a consensus for removal, but rather a consensus to retain this information but interweave it into the history of the development of the concept. There are at least two possible approaches here:

1. Say nothing about discovery except interspersed in the section about the development of the context.
2. Describe the history of discovery first, then refer back to it in the following section about the development of the concept

I think both approaches are valid; I would leave the decision up to editorial discretion. But it seems most commenters here argue against (2); in fact, a bare unqualified remove would argue against both approaches. But I reckon most of the remove !voters would be quite happy with (1).

—- YBG (talk) 01:11, 27 July 2024 (UTC)

I would be OK with (1) (said so below) so long as it is updated to modern thinking. Others, please yea or nay Ldm1954 (talk) 03:32, 27 July 2024 (UTC)

• Comment: @Double sharp: Yes, the subject content isn't about the history of the classification "nonmetal". That is why the content appears in its own section, "Discovery of applicable elements", after the section called "Taxonomical history". In this context, could you please reconsider your !vote? --- Sandbh (talk) 00:29, 26 July 2024 (UTC)

  Include some history, not necessarily in current form. Historical understanding of what a metL or non-metal was, was inevitably different and certainly evolved, so it is generally inappropriate to force modern concepts and classification on to historical events, it never works. A History section needs to describe events plainly, selecting as relevant those connected to understanding. The discoveries of what are today seen as non-metals are necessary to the growth of this understanding (or nobody would've come to the issue), but not sufficient, i.e. they are only a preliminary to the growth in understanding, which is the main thing to be explained. Chiswick Chap (talk) 02:27, 26 July 2024 (UTC)

  @Chiswick Chap, a comment. There is already a separate section Nonmetal#Taxonomical history which I think discusses exactly what you are referring to, namely evolution of the terms. I personally think that section could be slightly tighter, but I feel it has a place and nobody has suggested deleting it. What we are debating here is something different, namely the discovery of the 23 elements as a completely separate and independent section. The debatable section was placed after the Taxonomy section, with all the content already present in more detail in Discovery of chemical elements. Ldm1954 (talk) 03:13, 26 July 2024 (UTC)

  I discussed two things above. The Taxonomical history seems to cover the history of the concept, but not of discovery, which must as I said have preceded that of the concept. I'd have thought some sort of account of discovery is also necessary. Clearly here the finding of substances in nature (or by chemical analysis) cannot be fully separated from development of concept, since finding some yellow stuff does not mean you know you have a nonmetal element - it might be in modern terms a compound - so it would make more sense to weave the "discoveries" into the Taxonomical history. You may well be right that the debatable material is excessive for this purpose; but the current history may also be somewhat too light on the topic. Chiswick Chap (talk) 07:39, 26 July 2024 (UTC)

  I would support a remove and rewrite where the discoveries are weaved into the Taxonomy indicating how this influenced the interpretation of the term nonmetallic element. This would also be a way to introduce how the understanding of metal/not a metal changed in the 20th century from early band structure to more recent strongly correlated electrons and many-body physics/chemistry. Such a modification would both retain the focus on the topic and also connect to current research. I could draft the latter section if a concensus emerges. Ldm1954 (talk) 10:02, 26 July 2024 (UTC)

  I agree that this issue is nuanced, and not a slam dunk. In my opinion "nonmetal elements" cannot be "discovered". This is conceptual category, arrived at by analysis across a significant number of elements. This is a result of analysis, not something you find. Discovery of any one element tells you not at thing about the category. Only after you have many elements and in particular a large number of metals does the category emerge. Thus the key historical input is the elements that triggered the discussion of the category. Johnjbarton (talk) 21:58, 26 July 2024 (UTC)

  That "nonmetal elements" cannot be "discovered" is why the section in question is called "Discovery of applicable elements". This further explains why the section starts as follows:

  "While the concept of a chemical element came to fruition during the 18th and 19th centuries, some elements now classified as nonmetals (or sometimes as metalloids) were known and used from as early as antiquity, even if they were not recognized as such at the time."

  While it was the elements involved that led to the establishment of the category, they had to be first discovered. Given the intrinsic properties of nonmetals are elaborated elsewhere in the article, including a historical commentary about the discovery of relevant elements is justified.

  Historical commentary provides context to the scientific process and the evolution of chemical knowledge. Understanding when and how elements were discovered gives insight into the challenges and methodologies of early chemistry. Including historical anecdotes adds a human dimension to the scientific narrative, making the story of nonmetals more engaging and relatable. It alludes to the perseverance and ingenuity of the scientists involved.

  In terms of historical content, there are a few other items worth elaborating:

  • Phosphorus: Discovered as a by-product of attempting to create the fabled philosopher's stone, which was a legendary substance in alchemy believed to transform base metals into gold. This discovery illustrates the transition from alchemy to early chemistry.
  • Hydrogen: The discovery of hydrogen led to the development of acid-base chemistry, a fundamental area of study in chemistry.
  • Helium: Discovered off-planet before on-planet, highlighting the overlap between astronomy, spectroscopy, and chemistry. This demonstrates how advancements in one field can drive progress in another.
  • Noble Gases: The completely unanticipated discovery of the noble gases forced a rethink of the accepted understanding of the periodic table at the time, as these elements initially seemed to have no place within it. Additionally, nitrogen was referred to as the original "noble gas" before the discovery of the noble gases, due to its relatively inert nature.
  • Metalloids: The discovery of nonmetals sometimes counted as metalloids, such as silicon and germanium, subsequently enabled the establishment of the semiconductor industry in the 1950s and the development of solid-state electronics from the early 1960s.

  While maintaining an objective and factual tone is crucial for Wikipedia articles, integrating the human dimension where appropriate can enrich the content and provide a fuller picture of the historical and scientific narrative. — Sandbh (talk) 03:01, 27 July 2024 (UTC)

  The history of non-metal is exactly the same as the history of metals because non-metals are exactly that. Not metals. Go back in 10000 BC. Is water a metal? No. Then water is a non-metal. Is air a metal? No. Air is a non-metal.

  As refine your definitions of metals, so do non-metals get refined. There is never any discovery about non-metals made here. Headbomb {t · c · p · b} 04:24, 27 July 2024 (UTC)

  The scope of the article is the chemical elements that are not metals, rather than the term "nonmetal" itself. This aligns with the most common understanding of the term and adheres to Wikipedia's title naming conventions.

  I understand your point that nonmetals, as elements distinct from metals, have always existed. Including these historical narratives does not contradict this idea but rather provides a fuller picture of how they came to be understood as they are today. This historical perspective is valuable for readers and enhances the article by adding depth and context.

  The history of the discovery of what we now call metals and nonmetals is quite different. The discovery of the seven recognised metals in antiquity has no parallel. The early 19th-century discovery of metals that floated on water shattered the millennia-old conception of metals as ponderous substances. Additionally, I’ve previously mentioned the tumult caused by the discovery of the noble gases regarding their placement in the periodic table.

  Including these historical narratives enriches the article by illustrating the scientific process and the evolution of chemical knowledge. This context helps readers appreciate the challenges and breakthroughs that have shaped our modern understanding of nonmetals. — Sandbh (talk) 10:42, 28 July 2024 (UTC)

  According to @Sandbh:

  • "The scope of the article is the chemical elements that are not metals,"

  That is not correct. The article is about the category of elements referred to as the nonmetals. An article about a collection of elements is not notable unless there are references and the references here are about the category of nonmetal elements.

  Your comments about the history of metals that float and nobles gases are only relevant if you have a source that connects these events to the scientific process leading to the creation of the category non-metals. The lack of such sources is what makes the section under discussion unsuitable. By placing this material in the article you are implying a connection that you cannot document. Any source that documents specific "challenges and breakthroughs that have shaped our modern understanding of nonmetals" would change my opinion of the proposal. So far all I hear is the same argument over and over about the same off-topic content. Johnjbarton (talk) 22:48, 28 July 2024 (UTC)

  In writing that the article is about the chemical elements that are not metals, the context is that its title does not mean it is about a collection of elements—it is rather about both the constituents of the category, and the category. Humans, being incessable classifiers, attempt to sort out whatever consituents make up the kind of thing, nonmetals in this case, being studied, in order to improve their understanding of the subject matter. For nonmetals, this has been the case since at least 1844, when Dupasquier established a basic taxonomy of nonmetals to aid in their study. The nonmetal article therefore includes references to kinds of nonmetals e.g. noble gases, as well as the individual nonmetals. — Sandbh (talk) 10:32, 1 August 2024 (UTC)

  Retain. There is a prior implicit consensus, and we're supposed to preserve the value that others add (try to fix it rather than remove it). There was a claim that "nonmetals could not have been discovered before people knew they existed as a category"; to me, this is equivalent to saying "no elements could have been discovered before people knew they existed as a category". Given such a diverse set of ~23 elements, the only thing that makes them a category is our (silly) name — the fact that they are so different from the rest of the elements (metals), which are all alike. So, yes, the history of their discovery is the history of discovery of each of those elements, grouped by discovery methods or periods or people who discovered them. No big deal. I'd expect the same timeline for metals in "Metal", which is something I believe we have. Ponor (talk) 20:25, 29 July 2024 (UTC)

Include; I agree with Graeme Bartlett. Nerd1a4i (they/them) (talk) 22:29, 31 July 2024 (UTC)

Pinging past commentators on Nonmetal FACs

@Buidhe, Graham Beards, ComplexRational, Hog Farm, Double sharp, Nikkimaria, Materialscientist, Nick-D, YBG, Dirac66, Doncram, Petergans, Mirokado, CactiStaccingCrane, VanIsaac, Jo-Jo Eumerus, Ealdgyth, Guerillero, SandyGeorgia, Reaper Eternal, UndercoverClassicist, Smokefoot, Ajpolino, Licks-rocks, and Michael D. Turnbull: as past commentators on Nonmetal FACs.

Should this content on the discovery of the 23 nonmetals be removed from the nonmetal article?

RfC is just above.

Apologies for any double notifications. --- Sandbh (talk) 08:36, 25 July 2024 (UTC)

There are a few editors who have much more recently expressed opinions on aspects of this very extended discussion such as @Fishsicles, Ponor, Nerd1a4i, and Jähmefyysikko:. Added to be inclusive. Ldm1954 (talk) 09:09, 25 July 2024 (UTC)

I assume that @Sandbh and @Ldm1954 included all FAC participants and all recent talk participants, and that neither list was culled inappropriately. YBG (talk) 22:46, 25 July 2024 (UTC)

I culled nobody; I included everyone who has recently expressed an opinion here, and related discussions on WP:Physics & Nonmetallic materials, trying not to miss anyone. Culling obviously would be dishonest. I did not check the FAC. Ldm1954 (talk) 23:33, 25 July 2024 (UTC)

N.B., the original RfC was only posted by @Sandbh to Chemistry & Elements projects. I added Physics since they have been involved in discussions since nonmetals are very relevant in Physics. (The Materials Science project appears to be asleep.) It appears that @Sandbh has added Geology & Biology. Ldm1954 (talk) 00:25, 26 July 2024 (UTC)

Adding @Guerillero and Serial Number 54129:

Should this content on the discovery of the 23 nonmetals be removed from the nonmetal article?

RfC is just above.

I had some difficulty in discerning your user addresses when first compiling the list of past FAC commentators. --- Sandbh (talk) 00:20, 26 July 2024 (UTC)

Historically not a notable concept.

I had the opportunity to visit a UC library today. I looked through more than a dozen books on the history of chemistry. This included, for example, a 4 volume, 2000+ page work JR Partington, History of Chemistry https://doi.org/10.1007/978-1-349-00309-9. I found one and only one index entry for "nonmetal" and it did not discuss the concept as history. This does not prove the concept has no historical significance, but it casts doubt and the current refs on history of the topic are weak. Johnjbarton (talk) 01:41, 2 August 2024 (UTC)

If I went to the Library of Congress and looked at a dozen books on the history of the United States, I am quite certain that, even in a 2,000 plus page tome, you would find no reference to the history of the county I live in. If then the history section of the WP article on the county began with a summarizing statement that The historical development of the county was a complex spanning nearly nine decades, would you tag it {{dubious}} with a comment Historically not a notable concept? This would appear ridiculous to the half-million-plus residents, much less those who manage the local history museum.

Now, I freely admit that my analogy is a poor one, but I hope it causes you to rethink the strength of your argument.

The statement had been tagged {{citation needed}}, which is fair because while I recognize that although The widespread adoption of the term "nonmetal" followed a complex process spanning nearly nine decades is an honest attempt to write a wp:NPOV summary, it would be better if the summary were directly cited to avoid possible accusations of wp:SYNTH or wp:OR.

@Johnjbarton, I respectfully suggest that you change the tag from {{dubious}} back to {{citation needed}}. Thank you for considering this.

— YBG (talk) 03:38, 2 August 2024 (UTC)

@YBG As I understand your argument, "nonmetal" is too insignificant on the scale of "history of chemistry" to mention, in the same way that your county has had no noteworthy mentions in the history of the US. I agree that is a fair analogy, and matches the title of the Topic I used. (I could quibble about Partington having lugged all four volumes off the shelf: it may have some material about your county!).

My intent in going to the library was to add refs to what I think is a weak section. I found none.

Now look back at the section. We have one paragraph on Lavoisier's work, but it barely relates to "nonmetal" as described in the article. The secondary ref makes no connection between Lavoisier's categories and the topic.

The next paragraph starts with an unsupported claim and sentences about metalloids. Again no secondary refs. One encyclopedia entry. Then the Kemshead ref I posted about before and which is not a history.

Personally I do not believe "The widespread adoption of the term "nonmetal" followed a complex process spanning nearly nine decades". I believe the term nonmetal as discussed in this article arose in the 20th century, as one of several dichotomies opposite metallic bonding, as a side effect of the understanding of chemical bonding. That would be my honest attempt at a non-POV summary, but I do not need to provide a source for this because I did not include it in the article.

I think this section would be better if Lavoisier's work were positioned as and early attempt to develop "Types" as this would be easily supported. We should give up on the idea that nonmetal in the sense of the article is an old concept. It's only true in the "there exist materials that are not metals", which we have excluded from this article. Johnjbarton (talk) 17:05, 2 August 2024 (UTC)

@Johnjbarton and @YBG, I do think there should be some history. However, it does need some careful checking, and I request that you try and read and verify all the cited sources.

Why? I have been going over the sources in the table that was on different definitions. I have found and read most of them. Unfortunately 10 of the sources either did not support what was in the table, were on different topics or the pages did not exist. Several were duplicates, i.e. the standard band structure explanation or "atomic conductance" which is electrical conductance in molar units. Indeed from about 1950 all the (chemistry) textbooks that go into some detail use the band structure explanation and temperature dependence of conductivity. Some NPOV rewriting is needed. Ldm1954 (talk) 12:29, 5 August 2024 (UTC)

Everything that I have found points to the same conclusion: there is no such term as "the nonmetals" except in the narrow sense of "elements which are not metals". The nonmetals are not, in any source I have read, a category like "halogens" or "transition metals" or "lanthanides". See for example,

• Fluck, E.. "New notations in the periodic table" Pure and Applied Chemistry, vol. 60, no. 3, 1988, pp. 431-436. https://doi.org/10.1351/pac198860030431

Of course I cannot provide a reference to show that a non-thing like non-metals is not a thing! There are refs that use "nonmetals" for the category of elements listed here, but this is not chemistry but simply logic: many elements share the property of being metals, the rest are thus "nonmetals". The only common property is exactly one: not being a metal.

There isn't a history for the term "nonmetal" because it is not a thing. The closest we get is the current discussion, which I've fixed up the refs for. In the earliest days, "nonmetals" was a "Type" before elements were more broadly understood. My claims can be easily refuted with a reference and maybe there are a few but it's not a mainstream concept beyond a logical category. I've done what I can here. Johnjbarton (talk) 02:27, 6 August 2024 (UTC)

Dubious cites

Several inaccurate cites, they all need checking in detail:

1. Cites of p7 in [21] for "brittle or crumbly" which source does not say. The only relevant information is a discussion of brittleness of nonmetallic materials such as MgO on p270.
2. Cite of [26] for 1000 atom Se chains, where there is no source cited in the book so it is not a good source.
3. Cite of [68] for octet rule, where in fact the text says that is not a good approximation and VB should be used (changed)
4. Both As & graphite are semimetals, incorrect statement in Enf
5. The use of an O-level (< 16 years old) text book, i.e. Cambridge O Level Chemistry Book by B. Earl and Doug Wilford is dubious.
6. Citation to Sanderson 1957 quoted a page that did not exist (was the 1967 book meant?). In any case the ref has only been cited twice so removed as it is not really that relevant or accurate.
7. Temperature coefficient of resistivity is very much older than the table implied, it is in Kittel 1956. Date moved to 1956 (it might be earlier) and a relevant source added. Other dates are probably wrong.
8. Atomic conductance is just electrical conductance in different units; it is redundant so has been deleted.
9. The article about "3D conductivity" was misquoted, it is just another rephrasing of the established conductivity argument. Deleted from table.
10. The claim in the table that Horvath connects critical temperature to metal/nonmetal does not appear in the paper. Hence removed from the table.
11. The cite of Remy (1956) as "Minimum excitation potential" is inaccurate. He gives the standard band structures explanation. Removed.
12. The cite of Mann et al 2000 on configurational energy is invalid. The paper only discusses the d-block elements and makes no claims about metals versus nonmetals in general. The Wikipedia link also makes no such claims. Removed.
13. Johnson (1966) does mention physical state, e.g. gas, but then says it is not so good and lists the other standards such as conductivity etc. Hence removed from table as unverified.
14. Scott 2001 cites page 1781 which does not exist in any edition of the book (250-350 pages). Marked as dubious, perhaps delete later.
15. Povh & Rosin 2017 has no statements about thermal conductivity on p131. There is a short description on p173, but it does not call this a defining property. Deleted as unverified.
16. Brandt 1821, p5 is not even close to discussing metals and opacity. Deleted as very unverified and irrelevant.
17. Beach 1911 appears to have been copied from Origin and use of the term metalloid which has unrelated information. Since this is a very long book, without specific page number etc this source is not verifiable.
18. Harris 1803 provides the standard property list, the text misquoted what is stated.
19. Cyclopaedia: Or an Universal Dictionary of Arts and Sciences (1743) rambles for three and a half pages with statements such as differentiating gold, mercury and silver by how much sulphur is in them, that metals are transmutable into each other etc -- there is a link to an open source. While the statement about "heaviness" is there, it is not the focus of the article. I cannot consider this as a useful source so I am deleting it, whereas Harris 1803 is definitively reputable.
20. Jones citation is "Jones BW 2010, Pluto: Sentinel of the Outer Solar System" which is definitely not on distinguishing criteria of nonmetals. Marked for the moment as dubious.
21. Hare and Basche 1836 p310 is cited for inventor Humphry Davy made an important discovery that reshaped the understanding of metals and nonmetals. It says nothing like that on p310. Removed as unverified.

Ldm1954 (talk) 19:52, 5 August 2024 (UTC)

"where there is no source cited in the book so it is not RS."

That's not how RS's work. Headbomb {t · c · p · b} 16:58, 3 August 2024 (UTC)

The statement is an aside, not part of a discussion on Se. A review which is on the topic would be appropriate; a single aside is IMO not what should be used to verify a statement. Maybe not quite NRS, but certainly better should be done. Ldm1954 (talk) 17:26, 3 August 2024 (UTC)

Headbomb is right: That's not how RS’s work. The author of the source is a PhD physicist. They write, in discussing the properties of Se, that, “The most prevalent grey form contains large chains up to 1000 atoms long.” Not that it matters but this statement is self-evidently not an aside. I will revert the {{dubious}} tag. — Sandbh (talk) 11:19, 5 August 2024 (UTC)

The source has been changed to an adequately cited peer reviewed article that provides a mini review on linear Se chains and goes further into an analysis of the chains in amorphous Se. This validates the "long chain" statement; the 1000 atom number is speculative without much more sourcing so has been removed. Ldm1954 (talk) 11:55, 5 August 2024 (UTC)

Thank you for adding the article. I've reinstated the RS that you removed. The two sources are now present in the one cite. --- Sandbh (talk) 14:08, 5 August 2024 (UTC)

I will leave that although it is IMO inappropriate when a strong secondary sources already exists. Please note WP:RSCONTEXT:

Information provided in passing by an otherwise reliable source or information that is not related to the principal topics of the publication may not be reliable; editors should cite sources focused on the topic at hand where possible.

Ldm1954 (talk) 14:14, 5 August 2024 (UTC)

Advance apologies: It will take me some time to work through this list, in between RL obligations. — Sandbh (talk) 11:21, 5 August 2024 (UTC)

1. I concur. Have removed the source in question and replaced it with a relevant source. --- Sandbh (talk) 13:41, 5 August 2024 (UTC)

Timeline accuracy

I don't know who cobbled this together, but the dates don't check out on many things. For instance, the so-called Mott criteria, supposedly suggested in 2020. Work on this goes back to Goldhammer (1913) and Herzfeld (1927). Mott wrote about it in his book in 1990, but he came up with that criteria way back (1961? doi:10.1080/14786436108243318).

And yet we say 2020 because come people wrote a paper using the Mott criterion in 2020.

Utter. Nonsense.

This whole section should be jettisoned until we have actual sources discussing the actual history of metals.

Headbomb {t · c · p · b} 02:11, 6 August 2024 (UTC)

Yup, the dates are horrible and many of the sources don't verify (see my ever growing list #Dubious cites). Plus the most important definition, band structure, is conspicuously absent despite appearing in numerous chemistry texts books. It needs to be there. Ldm1954 (talk) 02:26, 6 August 2024 (UTC)