Talk:History of atomic theory

History of 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.

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October 15, 2006	Featured article candidate	Not promoted
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August 29, 2007	Good article reassessment	Kept
February 15, 2023	Good article reassessment	Kept
Current status: Good article

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Archives: Index 1

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Mass of an electron

@Johnjbarton: The article says that Thomson measured the mass of an electron to be 1/8000 of a proton. But I looked through Thomson's paper and he didn't measure the mass, but the mass-to-charge ratio. When was the mass measured? Was it Milikan's oil drop experiment? If you measure the charge of an electron and you already know the mass-to-charge ratio, you can then calculate the mass. Kurzon (talk) 12:00, 14 May 2024 (UTC)[reply]

I didn't find 8000, but I did edit the m/e section for the electron based on Whittaker. Johnjbarton (talk) 18:17, 14 May 2024 (UTC)[reply]

@Johnjbarton: In his 1899 paper, Thomson writes: "This mass is exceedingly small, being only about 1.4 × 10^-3 of that of the hydrogen ion". Does that mean the electron is 1,400 time smaller than hydrogen, or 1/0.0014 times smaller? Kurzon (talk) 18:35, 14 May 2024 (UTC)[reply]

"being only about" 1.4 times 1/1000 times hydrogen ion. So 700 times less massive, my mistake. (and it's not smaller but lighter) Johnjbarton (talk) 18:43, 14 May 2024 (UTC)[reply]

@Johnjbarton and Ajrocke: How did Thomson know the charge on a hydrogen ion is equal to the charge on an electron? Which papers did he lay out his proof? Kurzon (talk) 09:21, 15 May 2024 (UTC)[reply]

Doesn't this follow from charge neutrality? The hydrogen atom is neutral.--ReyHahn (talk) 09:29, 15 May 2024 (UTC)[reply]

Thomson measured e for ions and for photo-electrons. He measured m/e for cathode rays and photo-electrons. In his photoelectron paper he says

W. Wien (Wied. Ann. lxv. p.440) and Ewers (Wied. Ann. lxix. p.187) have measured the ratio of m / e for the positive ions in such a tube, and found that it is of the same order as the value of m / e in ordinary electrolysis; Ewers has shown that it depends on the metal of which the cathode is made. Thus the carriers of positive electricity at low pressures seem to be ordinary molecules, while the carriers of negative electricity are very much smaller.

Johnjbarton (talk) 22:04, 15 May 2024 (UTC)[reply]

Well I don't think at the time Thomson knew that a hydrogen atom had just one electron. Kurzon (talk) 09:59, 15 May 2024 (UTC)[reply]

Multiplier/multiples

@Johnjbarton: Let's revisit this issue.

In an April 1911 paper, Ernest Rutherford estimated that the charge of an atomic nucleus, expressed as a multiplier of hydrogen's nuclear charge (e), is roughly half the atom's atomic weight, based on how various types of metal foil scattered alpha particles.

I think it should be "multiplier".Kurzon (talk) 18:30, 18 May 2024 (UTC)[reply]

? I guess this is a quote from somewhere. But it is unrelated to the discussion on Rutherford scattering experiments. In the quote above "multiplier" seems fine to me. The other sentence was different and anyway I removed it for other reasons. Johnjbarton (talk) 19:06, 18 May 2024 (UTC)[reply]

GA concerns

I am concerned that this article no longer meets the good article criteria because there are uncited statements throughout the article, including entire paragraphs. Is anyone interested in fixing up this article? Z1720 (talk) 20:53, 5 October 2024 (UTC)[reply]

The other issue here is a large proportion of primary refs. I have this article on my todo list. I'm familiar with the sources from Thomson on. I'm currently working on Bohr model.

If you or anyone else added citation-needed tags I would fix them. Johnjbarton (talk) 22:10, 5 October 2024 (UTC)[reply]

@Johnjbarton: Sorry for not responding sooner: I added cn tags to the article per your request above. Z1720 (talk) 02:12, 27 October 2024 (UTC)[reply]

Excellent thanks! Johnjbarton (talk) 02:17, 27 October 2024 (UTC)[reply]

Rutherford's model is sometimes called the "planetary model"

The article says;

Rutherford's model is sometimes called the "planetary model".

With a ref to

"Rutherford model | Definition & Facts". Encyclopedia Britannica. Retrieved 23 August 2021.

While working on Rutherford atom I looked into many references discussing planetary models. Planetary models appeared before 1911, Rutherford's model was not planetary (he made no comment on the electrons), and the concept of associating planetary models with atom appeared long after 1911, in association with Bohr's model of circular orbits. Please see Bohr_model#Symbolism_of_planetary_atomic_models and the ref below.

The Britannia site has other errors, eg "Physicist Ernest Rutherford envisioned the atom as a miniature solar system,". A comprehensive history says "Rutherford did not specify the electronic arrangement..." Heilbron, John L. (1968). "The Scattering of α and β Particles and Rutherford's Atom". Archive for History of Exact Sciences. 4 (4): 247–307. doi:10.1007/BF00411591. ISSN 0003-9519. JSTOR 41133273.

I think this sentence should be removed despite the reference. Johnjbarton (talk) 23:11, 23 October 2024 (UTC)[reply]

I checked the plum pudding model for consistency, and its cited content agrees that while Rutherford's model was a dense positive center and electrons around it, it did not have any specific structure to the electron pool or its motion. DMacks (talk) 23:40, 23 October 2024 (UTC)[reply]