# Talk:Atomic theory

Atomic theory has been listed as one of the Natural sciences good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it.
Article milestones
Date Process Result
October 21, 2006 Peer review Reviewed
October 28, 2006 Good article nominee Listed
November 3, 2006 Featured article candidate Not promoted
November 26, 2006 Featured article candidate Not promoted
February 12, 2007 Featured article candidate Not promoted
March 30, 2007 Featured article candidate Not promoted
August 29, 2007 Good article reassessment Kept
Current status: Good article

## John Dalton

I've done a lot of googling on the net trying to find precise details on how exactly Daltin arrived at his atomic theory, and some of the information has been contradictory. When I wrote this section, I put nitric oxide and oxygen as one of the pairs of gases he studied. Some articles said Dalton referred to the former as "nitrous gas", and that this gas was really nitric oxide (NO). The equations and ratios I wrote were an educated guess on my part rather than a quotation from what Dalton actually did. However, another wikipedian rewrote it to be nitrous oxide (N2O), which changes the equations somewhat. Are there any experts on Dalton's life and work who can give a definite answer to this? Could some student here please ask their chemistry professor?

I removed this paragraph:

In some cases the study of a property at atomic level is very complex and easier results are obtained with a study at a bigger scale. This does not means that atomic theory does not work in these cases. The problem is the mathematical complexities given by treating such problems with the atomic theory. Till nowdays there are no cases where atomic theory does not work, there are only cases in which the result is more easily obtained, in the limit of the wanted approximation, with easier theories. Despite that it may be of some worthness to point out that a general vision should always kept and considered, and to consider the world or the entire universe only as series of atoms is reductive.

Aside from its very strange usage ("Till nowdays", "some worthness"), I think this is factually incorrect. There are many cases where atomic theory does not work, which is why a further reduction to quantum mechanics was required. I would be happy with a rewriting of this paragraph to express the fact that large-scale abstractions are still useful for thinking about things, as long as it is correct. Brighterorange 7 July 2005 23:25 (UTC)

You did the right thing. It was too generally worded to get any interesting meaning out of it, its vague. Re-write if you wish. linas 04:35, 10 July 2005 (UTC)

I removed a small paragraph mentioning an early, discarded theory of cubical atoms from the last section. I believe this article should focus only on the chain of developments that led to modern accepted atomic theory (in particular, give the reader a basic idea of how scientists figured it out). Dead ends and tangents can make things a little confusing.Kurzon

You really do have a great article, but I have one point...it was Dalton's "Atomic Theorie" he really did spell it like that...74.237.244.61 22:26, 18 February 2007 (UTC)

I've made some corrections and additions requested by the first writer in this section. The writer's "educated guess" was very close to the truth, but not quite, as the multiple for Dalton was nitrous air, not oxygen. Dalton's "nitrous air" is nitric oxide, not nitrous oxide (the latter of which he called by that name). Dalton spelled the word "theory" just as we do. Ajrocke (talk) 14:33, 13 February 2008 (UTC)

I think he just took the hint from Guy-Lusaac law of combining volume. But, it is hard with out knowing the starting point. The table he got is way off. 76.219.230.165 (talk) 03:07, 19 January 2013 (UTC)

## Visualizability

"Up until the late 20th century, atoms could not be directly observed. Beginning as a purely philosophical concept, their existence and nature were explored indirectly by correlating knowledge gained through various scientific experiments over the course of the past few centuries." I'm not sure what is meant here by "directly observed" — they can still not be "directly" observed any more than they once could. They can be indirectly observed, and with far better precision than they could before, but "directly"? Though I am usually averse to Bohr-style philosophical discussions of what "observation" means, when we are talking about things as small as atoms I think it becomes impossible not to be very careful in our terminology. --Fastfission 19:51, 15 October 2006 (UTC)

Don't field ion microscopes count as direct observation? Kurzon 14:36, 17 October 2006 (UTC)

## Philosophical Atomism vs. Atomic Theory.

This is already a great article.

I have a problem: Philosophical atomism addresses the concept that the matter in the universe is composed of indivisible units. This philosophy is not invalidated by "splitting the atom". Basically, the fact that we can split an "atom" merely means that we assigned the name "atom" to the wrong physical unit.

The definition of an "atom" according to the philosophers is "an indivisible entity." It is not the fault of the philosophers that Dalton and other early chemists incorrectly attached the word "atom" to an entity that we later discovered to be divisible.

## GA Passed

Congratulations, this article has passed the GA nominations. As a suggestion I would suggest having 2-3 citations in each section. Tarret 19:25, 28 October 2006 (UTC)

### GA sweeps review

Re-reviewing the article on 29 August 2007 to confirm that it still meets the GA criteria. Other than a few minor reference formatting fixes, this article continues to meet the criteria, and will continue to be listed as a Good Article. Dr. Cash 16:47, 29 August 2007 (UTC)

## Isotopes

The discovery of isotopes is commonly attributed to Frederick Soddy (at least he is the one who got the Nobel Prize for it). I don't know much about the claim that it was Thompson, but if there's something to it the article should also mention Soddy and explain. If not, the attribution should be replaced by the correct one. -Itub 18:37, 26 March 2007 (UTC)Small TextSmall Text${\displaystyle SmallText}$[[Media:#REDIRECT Example.ogg
Strike-through text]]

Well, Thomson generated the DATA for neon, but he didn't interpret it correctly at first. It sat there until 1920, when somebody realized what it was. There's also a difference between the guy who first understood that there could be isotopes of LIGHT and STABLE elements (like neon) vs the heavy and radioactive stuff that everybody was working with. I'll read INWARD BOUND on the subject and see if I can sort it out a bit better.SBHarris 18:52, 26 March 2007 (UTC)

Soddy's Nobel Lecture and Aston's Nobel Lecture are illuminating. There were many "discoverers" of isotopes in the experimental sense, but Soddy was the one who got the credit for coming up with the concept and clarifying the confusion caused by the various decay products of uranium and thorium. Apparently Thomson was indeed the discoverer of isotopes of light elements, but the isotope concept was mostly formed already based on the radioactive elements. Thomson's former pupil, Aston, got the Nobel Prize for improving the technique and applied it to the discovery of isotopes of many other elements. Note, however, that the importance of Thomson's discovery had already been recognized by Soddy in 1913. He said "The discovery is a most dramatic extenions of what had been found for elements at one extreme of the Periodic Table to the case of an element at the other extreme, and strengthens the view that the complexity of matter in general is greater than the periodic law alone reveals". --Itub 11:30, 27 March 2007 (UTC)

I would like to suggest that at the atomic level the complexity of the matter involved is not nearly as complex as are the conceptions and mathematics dreamed up by people who are trying to explain it.WFPM (talk) 02:55, 4 May 2010 (UTC)

## Grammar Question

Is this a sentence? Or, in a nutshell, the idea that all things are made of atoms. —Preceding unsigned comment added by Anthon01 (talkcontribs) 20:44, 23 January 2008 (UTC)

I'm going to fix it. Anthon01 (talk) 21:48, 26 January 2008 (UTC)

## Looks like error

I'm just learning English, but from the sentence "Further experimentation by Rutherford found that the nuclear mass of most atoms exceeded that of the protons it possessed" I made a conclusion that the mass of an atom is greater than the sum of mass of separated protons. The matter is that the mass of an atom is less than sum of separate nucleus, because some part of the mass was converted to binding energy. —Preceding unsigned comment added by 82.207.2.194 (talkcontribs) 07:15, 24 February 2008

The sentence refers to the understanding of the nucleus prior to the discovery of the neutron (which makes up more than half the mass of alomost all nuclei) and is unrelated to the more recent concept of binding energy. Vsmith (talk) 15:33, 24 February 2008 (UTC)

## Confusing sentence introducing uncertainty principle

The article says, "Since a wavefunction incorporates time as well as position, it is impossible to simultaneously derive precise values for both the position and momentum of a particle for any given point in time," but I am not sure what this even means.

An object containing information about time and position has absolutely nothing to do with uncertainty principle. For example, a trajectory, or, for a real life example, your GPS trace contains information about both time and position but to the idealization done in making these, both position and momentum are precisely known.

IMHO, a better introduction to uncertainty principle should begin from the fact that matter is "wave"---and waves, whether it's classical like water waves or quantum mechanical like matter waves, cannot have both the well-defined momentum (which is related to the wavelength) and well-defined position (which is related to localization). —Preceding unsigned comment added by Novakyu (talkcontribs) 03:23, 21 December 2008 (UTC)

We're not talking about where a particle is, because it is where it is. Were talking about where a particle can be measured to be and with what accuracy of measurement.WFPM (talk) 03:33, 4 May 2010 (UTC)

## Perrin, Mach, brownian motion, Feyman

This entry is regrettably silent about Ernst Mach's skepticism re atomism. It has only one brief paragraph on how Einstein's paper on brownian motion, and Jean Perrin's careful estimate of Avogadro's number, convinced almost everyone by 1910-15 that atoms were indeed real. Also, when Feynman was asked to state the single most important scientific fact discovered from Galileo onwards, he said "the world is made of atoms."132.181.160.42 (talk) 01:31, 21 April 2009 (UTC)

Please feel free to edit the article, provided that any new or changed material is supported by reliable sources. Finell (Talk) 01:39, 21 April 2009 (UTC)
There are far too many dead-end theories in the study of matter. This article concentrates on the chain of events that genuinely pushed modern accepted theory as we know it.Kurzon (talk) 20:33, 20 August 2009 (UTC)

## Leucippus the ‘father of atomic theory’ nowhere to be found?

I find it strange that Leucippus, the originator of atomic theory, and his followers Democritus, Epicurus, Lucretius, are nowhere to be found in an article on ‘atomic theory’? I do note that he was in the original 2004 stub version, but seems to have been removed, to the relegated atomism article. When someone thinks ‘atomic theory’ the first names that come to mind are either Leucippus (or Democritus) or Dalton. I would suggest someone do a rewrite of this article to reflect this simplicity. The following timeline I wrote up today might lend some guidance on the basic framework of atomic theory:

I hope this input helps? --Libb Thims (talk) 23:54, 8 July 2010 (UTC)

I agree and I've added a section on atomism. Λυδαcιτγ 00:57, 9 December 2012 (UTC)

## Lochschmidt

I was reading the article about Johann Josef Loschmidt, and it says that Lochschmidt estimated "in 1865 the size of the molecules that make up the air:[2] his result was only twice the true size, a remarkable feat given the approximations he had to make." I jumped to this article, because I was hoping to find a description of what method he was using 1865, but there is no reference at all to this guy. Does anybody know something more? Thank you. If relevant, maybe it could also be added to the historical part in this article. KlausN (talk) —Preceding undated comment added 20:24, 10 September 2010 (UTC).

## Controversy

I added the section on the controversy about the existence of atoms. I thought this should be a separate article as it spoils the flow a bit, but the editors would not allow a new page so I have put it in here. — Preceding unsigned comment added by Mathew Rammer (talkcontribs) 20:00, 4 March 2012 (UTC)

I removed it because it's tangential. There are lots of dead end theories, too many to mention.Kurzon (talk) 20:31, 19 December 2012 (UTC)

## history of science

Science evolves and changes. Vitalism should be included as part of that change in this article. It should link in a way that allows tangenital stuff to be reached by linking off page, not removed to only have long equations. — Preceding unsigned comment added by 88.117.37.20 (talk) 20:43, 1 December 2013 (UTC)

## Animation for Bohr model

In the animation for the Bohr model, the linear velocity in the outer orbit appears to be higher than the linear velocity in the inner orbit. In my understanding of the Bohr model, it should be the other way round: the linear velocity should be inversely proportional to the radius of the orbit. Robamler (talk) 11:15, 4 August 2014 (UTC)

OK, Robamler, so the electron when on the outer shell should take four times as long to complete a single orbit than on the inner shell?Kurzon (talk) 08:57, 12 August 2014 (UTC)

## Vandalism

According to stats.grok.se, this time of year is when instances of vandalism to this article spikes. The school year has started.Kurzon (talk) 16:35, 4 September 2015 (UTC)

## Assessment comment

The comment(s) below were originally left at Talk:Atomic theory/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

 I rated it A as it seems like a very good article (also a FAC) it is also in my opinion a topic very important within the field of physics! Snailwalker

Last edited at 14:36, 12 February 2007 (UTC). Substituted at 08:33, 29 April 2016 (UTC)

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