Talk:Atom

English

In the opening paragraph the writing uses "less" when talking about things that can counted ("less electrons"). I suggest the corrected phrase should be "fewer electrons". Use "less" when talking about things that cannot be counted e.g. "less sugar means fewer sugar crystals". — Preceding unsigned comment added by 174.34.217.49 (talk) 14:20, 28 October 2011 (UTC)

Changed, thanks. Materialscientist (talk) 14:23, 28 October 2011 (UTC)

Book reference

Is there room in the book reference section for Asimov's book "Atom, Journey across the subatomic cosmos, Penguin Books 1992.WFPM (talk) 22:20, 26 November 2011 (UTC) ISBN 0-452-26834-6

Can it be used to cite something? Regards, RJH (talk) 18:32, 13 December 2011 (UTC)

Well you know Asimov! He talks interestingly about everything. And he almost makes you think you should understand it! And remember that he died in April 1992 and the book was published in August 1992.WFPM (talk) 10:16, 14 December 2011 (UTC)

Yes I do. However, the Book References section is intended for citations of material in the article. If it can't be used for that purpose, then I think the book would perhaps be better placed under a Wikipedia:Further reading section heading. Thanks. Regards, RJH (talk) 15:34, 14 December 2011 (UTC)

You might note that the book is not among those listed in his biography. But it's a good chronological discussion of science progress, and probably his most up to date writing. And he must have had a fantastic memory.WFPM (talk) 23:53, 14 December 2011 (UTC)

OK! At your instigation, I reread it, and it's a tour de force and chronological history of the physical/chemical history and concepts of atomic physics as only Asimov could write it, (328 pages). But he still models nucleons with spheres, which should be banned, and I like magnetized cylinders better.Regards.WFPM (talk) 01:02, 16 December 2011 (UTC)Truman Talley Books/Plume

MASS: An update to nuclear properties is needed

The large majority of an atom's mass comes from the protons and neutrons that make it up. The total number of these particles (called "nucleons") in a given atom is called the mass number. The mass number is a simple whole number, and has units of "nucleons." An example of use of a mass number is "carbon-12," which has 12 nucleons (six protons and six neutrons).

This statement should be changed. Mass Defect is an important concept of the mass of a nucleus and as such, should be included in this section. — Preceding unsigned comment added by 108.17.134.163 (talk) 09:50, 14 April 2012 (UTC)

The mass number is defined to be the number of nucleons. Mass defects are irrelevant here. Headbomb {talk / contribs / physics / books} 13:58, 14 April 2012 (UTC)

Classification of quarks

In the article is the sentence:

The quark belongs to the fermion group of particles, and is one of the two basic constituents of matter — the other being the lepton, of which the electron is an example.

I find this somewhat missleading: It sounds like there would be two types of particles: fermions and leptons. I would like to suggest to replace the sentence by something like:

The quarks and the electron belong to the fermion group of particles.

It is maybe the best to leave the classification of fermions into leptons and quarks to the standart model page. That way the paragraph only contains the two distinct classes fermions and (gauge-) bosons.

--Falktan (talk) 15:06, 19 June 2012 (UTC)

I think it could be re-written in a manner that retains the intended information. Perhaps:

Quarks and electrons are the two basic constituents of matter, and together they form the fermion group of particles.

Regards, RJH (talk) 15:26, 19 June 2012 (UTC)

Good idea. However, in order to continue being pedandic: One should maybe write

..., and both belong to the fermion group of particles.

The reason is, that there are also other fermions (e.g. the muon or neutrinos).

Falktan (talk) 15:33, 19 June 2012 (UTC)

True. In that case:

The quark is one of the two basic constituents of matter — the other being the lepton, of which the electron is an example. Both quarks and elecrons belong to the fermion group of particles.

Regards, RJH (talk) 17:11, 19 June 2012 (UTC)

I think we are getting closer :)

I still would leave the class of leptons out here, since the electron is not only an example, but the only lepton that plays any role at all. If not filled with any further information the word lepton is meaningless here anyway.

Regards, Falktan (talk) 19:41, 19 June 2012 (UTC)

Well, the subject of the paragraph is the quark. The lepton is mentioned as a contrast to the quark, and the electron is given as an example. Getting rid of lepton kind of defeats the purpose of the sentence. Regards, RJH (talk) 21:59, 19 June 2012 (UTC)

We don't need to mention fermions or leptons. Or hadrons or mesons. What we want to say is that ordinary matter (i.e., atoms) are made of two basic type of particles that have rest mass: quarks and electrons. Other massless particles (the gauge bosons) paritipate by creating the forces that hold quarks and electrons together to form atoms and matter. But that's pretty much it. SBHarris 23:29, 19 June 2012 (UTC)

In that case there's no need to mention electrons either because it's out of scope because of the exclusion of leptons from the sentence. I suggest changing it to:

The quark belongs to the fermion group of particles, and is one of the basic constituents of matter.

Regards, RJH (talk)

Agreed. We should throw out the electrons here. Actually the remaining sentence is not so meaningful either. I would even consider removing the hole sentence, or at least the part about "constituents of matter". This point is a bit tricky: Even though the quarks are the only particle in the nucleus having a rest mass, also the gluons play an important role for the overall mass of the nucleus, as can most clearly be seen from the mass defect. I would leave this hole point to the articles about protons and neutrons. So my suggestion would be

In the Standard Model of physics, both protons and neutrons are composed of elementary particles called quarks. There are six types of quarks, each having a fractional electric charge of either +2⁄3 or −1⁄3. Protons are composed of two up quarks and one down quark, while a neutron consists of one up quark and two down quarks. This distinction accounts for the difference in mass and charge between the two particles. The quarks are held together by the strong nuclear force, which is mediated by gluons. While the quarks are fermions, the gluon is a member of the family of gauge bosons, which are elementary particles that mediate physical forces.

For comparision the original:

In the Standard Model of physics, both protons and neutrons are composed of elementary particles called quarks. The quark belongs to the fermion group of particles, and is one of the two basic constituents of matter—the other being the lepton, of which the electron is an example. There are six types of quarks, each having a fractional electric charge of either +2⁄3 or −1⁄3. Protons are composed of two up quarks and one down quark, while a neutron consists of one up quark and two down quarks. This distinction accounts for the difference in mass and charge between the two particles. The quarks are held together by the strong nuclear force, which is mediated by gluons. The gluon is a member of the family of gauge bosons, which are elementary particles that mediate physical forces.

I moved the part about fermions to the last sentence. I would also consider throwing out or rephrasing the sentence

This distinction accounts for the difference in mass and charge between the two particles.

Regards, Falktan (talk) 12:51, 20 June 2012 (UTC)

I've simplified this a bit. This is an article on atoms, not the subatomic particle zoo. In an article on Alaskan sled racing, we do not mention the total number of dog breeds in the world, or the existence of chihuahuas. There are two types of quarks in atoms, and we can mention those. For the rest of the quark types, see the links, or subarticles. Likewise, if the electron is the only lepton you see making up an atom, you don't need to mention leptons. If neutrinos, newly minted, come out of atoms in decay, or muons can be externally added to atoms for a brief time, you can mention those particles, but the reader STILL has no reason to care that particle-physicists classify these also as "leptons"-- who cares?. It's irrelevent to "atoms." Save it for the article on leptons!

For the same reason, we really don't want to discuss the origin of the atom's mass here, since that leads into the origin of baryon mass, which is a complicated and ill-understood subject. Save that for the baryon article, or the articles on proton and neutron, where it is needed NOW and doesn't exist . Only 1% (or so) of baryon mass is due to rest mass of quarks, but there exist also sea quarks (virtual quarks), the mass of the quark kinetic energy, gluons with their energy (and therefore invariant mass) and other fields (static electric fields have mass, even though made of virtual photons, not real ones).

Somwhat likewise, the "mass defect" of nucleon binding is also not worth looking at mechistically. It's not just "quarks." Just say that it never exceeds 1% of nuclear mass (as compared with the free baryon masses in toto-- that 1% figure occuring again here, is coincidental, and of course can be smaller). This missing mass would actually be twice as large as it is, if not for the mass of the static electric potential energy *added* (not subtracted) when the positive charges were squashed together to make nuclei. This electric added-mass is always more than made up for, by missing mass from nuclear force field destroyed, but this nuclear force field is made of virtual mesons (pions and some rho mesons) and we don't want to go THERE, either! No. We can (maybe) just note that nuclear force is more energetic (in terms of potential) than the electric field potential, and that's why nuclei stick together.

But fission destroys electric potential at the expense of creating nuclear potential, and fusion does the opposite (destroys nuclear potential and creates electrical potential, as charges are pushed together) and that is all a matter of discussion in THOSE articles (nuclear fission and nuclear fusion, with perhaps some more in binding energy and atomic nucleus). But atom is not the place for it, as we haven't room. SBHarris 18:04, 20 June 2012 (UTC)

I totally agree. I like the changes in the article. Thanks, Falktan (talk) 11:53, 21 June 2012 (UTC)

Please add 'positronium' as another example of exotic matter

Positronium. I'd do it myself, but as you know the article is in lockdown. Thanks. 24.79.75.240 (talk) 07:36, 5 August 2012 (UTC)

 Done by adding the category:exotic atoms to the this section, which provides a list including Positronium. Also added the p. exotic matter with the same idea. (You could also get an account), Cheers, -- chat  O'Brien  08:41, 3 December 2012 (UTC)

The big bang, hydrogen not being mentioned.

I remember watching the talk show something from nothing with evolutionary biologist Richard Dawkins and Lawrence Krauss, Lawrence said that the first element created after the big bang were hydrogen helium, and a bit of lithium. Why did you not put hydrogen there, And protons and electrons were created 3 seconds after the big bang. — Preceding unsigned comment added by Anastronomer (talk • contribs) 09:58, 20 October 2012 (UTC)

Please sign your talk page messages with four tildes (~~~~). Thanks.

As you can see in the opening sentence of Big Bang nucleosynthesis, this nucleosynthesis does not produce hydrogen. It produces hydrogen isotopes and other nuclei from hydrogen. Cheers - DVdm (talk) 12:07, 20 October 2012 (UTC)

Allotropes

In the section on 'States', a correction needs made. The article is locked, so I can't. The article currently reads:

   "Within a state, a material can also exist in different phases. An example
   of this is solid carbon, which can exist as graphite or diamond."

This is not a phase. It is an allotrope. See the Wikipedia article on Allotropy. The statement should instead be worded:

   "Within a state, an element can also exist as different allotropes. An
   example of this is solid carbon, which can exist as graphite or diamond."

Perhaps even linking 'allotropes' to the Wikipedia Allotropy article.

Thanks!

66.62.194.228 (talk) 00:37, 17 November 2012 (UTC)

Fixed. Get a username , make 10 good edits, wait 4 days, and you too can edit these " locked" articles , which are only protected against IP editing. SBHarris 09:38, 18 November 2012 (UTC)

Changes in Atom #Energy levels

I explain why I made so radical changes in the section. It was apparently well-written (and referenced), but had a high density of errors. Namely:

1. “Main articles: Energy level, Atomic spectral line” — a bad idea. The former is a universal, general concept. It does not (and should not) explain electron's levels in atoms. The latter is a redirect to a medium-sized section in Spectroscopy. So, there is no "main article" unless somebody goes to create it.
2. “When an electron is bound to an atom, it has a potential energy that is inversely proportional to its distance from the nucleus” — first of all, it is not true because of interactions between electrons. Second, the potential in a dynamical equation does not depend on whether electron is “bound” or “unbound”, so this wording induces a confusion between the cause (the potential energy) and the consequence (the energy spectrum).
3. “This is measured by the amount of energy …” — no, absolutely. The potential energy (i.e. its dependence on the position vector) is determined theoretically. No experiment can measure it on the atomic scale.
4. “The lowest energy state of a bound electron is called the ground state” — it’s a crap. Is "1s" an “electron’s ground state”? Does somebody actually speak about the ground state of a single electron?
5. “while an electron at a higher energy level is in an excited state” — the same crap. Anywhere higher than 1s an excited state? For lithium, beryllium, etc.? Can somebody open that book and paste here the actual text?
6. “For an electron to transition between two different states, it must absorb or emit a photon” — from a factual (not QED) perspective, no. It can collide with something else.

Objections? Incnis Mrsi (talk) 20:43, 10 February 2013 (UTC)

individual

the english word that matches the greek word is individual. we dont say indivisible (αδιαίρετο) or uncuttable (άτμητο) in greek. and i think it is important cause the meaning changed with chemistry. i mean until the microscope was invented or Hook's Micrographia, people didnt talk about microorganisms Wassermagier (talk) 17:14, 7 March 2013 (UTC)

Article name change?

Now, I know that people generally do not like their words to be "touched", so I hope that this simple suggestion will not offend anyone. After all, we do "touch" other people's words.

The Etymology section in this article reflects not only the etymological and morphological meaning of the word, "uncuttable" or "indivisible" (which we've hammered into "the smallest particle of a chemical element that retains its chemical properties"), but also the fact that the notion of chemical units being atoms is not unanimous across scientists (see references 5, 6 and 7 in the article).

Would it not be a move towards NPOV if the article's title were changed to something less debatable, such as "chemical element", or "chemical unit" if the former seems to suggest the substance, rather than the particles, and make the entry Atom a redirection to this page? As it stands, Wikipedia seems to be positioning itself with those who call chemical units "atoms", and only marginally recalling that there is an ongoing debate about the appropriateness of the name.

But it is only a suggestion. Have a good day. Abedul69 (talk) 16:08, 23 March 2013 (UTC)

Please "touch" them words :) It is nice that you chose to make suggestions here, rather than boldy touching. Indeed, the concept of atom has changed since Dalton and any definition provided now will likely evolve as we learn more. And that last bit of text in the article from The God Particle seems a bit off as we have no way of knowing what the ancient philosopher types were "really" talking about. The atom concept remains valid in chemistry even tho we know it is no longer "the smallest". We (as in Wiki editors) don't redefine things, we just report what is the usage in reliable sources. If and when the preponderance of sources say "atom" is defunct - then we can also. Until then: atom it is. Cheers, Vsmith (talk) 17:33, 23 March 2013 (UTC)

In 2007 you said that you need to read guidelines. Really, read WP:POVNAME please – the problem does not exist. Also, atom represents a chemical element, but is not a chemical element, just like a molecule is not a chemical substance, a snowflake is not snow, etc. The proposed term Find sources: Google (books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL, first, does not exist, and second, would be even more ambiguous – a unit of what? Incnis Mrsi (talk) 17:40, 23 March 2013 (UTC)

Anaxagoras

What about the Ionian School and Anaxagoras?

Why is the history section bungled?

More elaboration is needed about Ionian Greek Atomic Theory (philosophy). This article has it wrong, or very incomplete.

The error was obvious and the article does not give an old enough date for the ancient Greek atomic theory. Anaxagoras was born 510 BC and as many know the Ionians are the creators of the atomic model and cosmic mind. Democritus was from the Traki city state in northern Greece and lived slightly later (at least 50 years).

The Ionian Atomic Theory is famous to anyone that reads philosophy; Wikipedia editors have just botched it.