Talk:Principal quantum number

m0 undefined

Please define m0. is it m_e, the mass of electron ? — Preceding unsigned comment added by Fabrice.Neyret (talk • contribs) 09:43, 14 March 2019 (UTC)[reply]

Untitled

Aren't they the s, p, d and f orbitals? I'm confused. Jonathan Grynspan

s,p,d,f are for the orbital angular momentum (or azimuthal to give its ancient name) quantum number. I've put the vital word "average" in to qualify the distance of the electron from the nucleus - it is by no means fixed! --Ian 08:06, 30 Jan 2005 (UTC)

Radial quantum number

Why does radial quantum number redirect here? I have always been taught that the radial quantum number is:

$n_{r}=n-l-1$

Being equal to the number of nodes in the radial wavefunction. Does wikipedia call this something else? --Zapateria 17:16, 6 June 2006 (UTC)[reply]

Tagged info on the radial quantum number onto the end of the article but think my formatting needs sorting out. Zapateria 17:48, 7 February 2007 (UTC)[reply]

wave/particle

I'm having trouble with the following line: The energy of any wave is the frequency multiplied by Planck's constant. This causes the wave to display particle-like packets of energy called quanta.
There is no 'wave', nor any 'particle': there is just a quantum, namely the electron. We just visualize it as a wave or a particle, depending on the interaction it is undergoing, but it is neither! The fact that the electron has a certain energy does not cause it to do anything.
I know that the energy of an electromagnetic wave is equal to the frequency multiplied by Planck's constant. Does this hold for electrons? I vaguely seem to remember calculating the wavelength of a tennisball once... Even so, this just tells us the frequency from the (known) energy, it is not an explanation of quantization effects.
--GilHamiltonTheArm 14:21, 21 November 2006 (UTC)[reply]

Why were the Orbit shells Named "K,L,M,N,O..."?

I have to do a small research for my course about Why was it named K,L,M,N,O.... , rather than A,B,C,D... , and i got quite lost while researching for it. —Preceding unsigned comment added by SherifHagar (talk • contribs) 16:43, 25 February 2010 (UTC)[reply]

Need an expert in this field to supply whatever is apparently missing from this sentence.

The following is the current second sentence in the introductory first paragraph. "As n increases, the electronic shells becomes more and the electron spends more time farther from the nucleus." Please fix. Thanks — Preceding unsigned comment added by 97.125.81.247 (talk) 18:47, 19 January 2016 (UTC)[reply]

Just a beginner trying to figure out how to notify of a small thing to add:

And, thanks so much for this article, clever helpful people who made it! Can we add complete definition of variables in Bohr's equation. So great to have this article! On a personal note, I'm note sure I've added a comment to this page in the right way...only just joined Wikipedia :)WikiStudent 23:34, 4 January 2020 (UTC) — Preceding unsigned comment added by Researchgatematerials (talk • contribs)

Elevator analogy seems out of place

Sometime in the past year (?) someone added an analogy to elevators in the intro: "For an analogy, one could imagine a multistoried building with an elevator structure. The building has an integer number of floors and a (well-functioning) elevator which can only stop at a particular floor. [...]" I think this metaphor is out of place, clumsy, and unhelpful. For example, the term "shell" is already invoking a better metaphor. A5 (talk) 19:44, 8 August 2018 (UTC)[reply]

OK I decided to remove it myself.A5 (talk) 21:11, 8 August 2018 (UTC)[reply]

I think the elevator analogy can be helpful as an introductory analogy. If you have some familiarity with quantum mechanics, it is a little clumsy, but this is a wikipedia page for a very basic QM concept, and I don't think we can assume all readers will be proficient in QM. It's a standard example used elsewhere: Astronomy Made Simple By Kevin B. Marvel, Ph.D. page 46:

"Electron energy levels are distinct, like floors on an elevator building. When riding in an elevator, you can get off only where a floor exists; you can't get off halfway between two floors. Similarly, electrons can exist only in particular orbits or energy levels, not in between."

Lasers by Hal Hellman, page 14:

"We might think in terms of an elevator that can only stop at the various floors of an apartment building. Each upper floor is like an orbit of the electron. But you get nothing for nothing in the world of physics, and just as it takes energy to raise an elevator to a higher floor, it takes energy to move an electron to an outer orbit."

I suggest we keep the elevator analogy, with a note that is in fact is not as rigorous as something like defining it formally as a good quantum number. Forbes72 (talk) 19:24, 3 October 2018 (UTC)[reply]

Source of emission spectrum of an element

The "Derivation" section says "The difference between energy levels that have different n determine the emission spectrum of the element". Can emission lines not be generated by energy level changes with the same n, ie, within the same shell? See for example the image in Principal series (spectroscopy), which shows a 3p-3d transition. As I understand the notation, both states are in the same n=3 shell.

Certainly the difference between energy levels in different shells contributes to spectra, but that is not the sole source of spectra as this seems to suggest. Either "determine" is an overstatement, or "different n" is too restrictive. Perhaps "The difference between [available] energy levels determines the emission spectrum..."? Captain Puget (talk) 14:44, 2 May 2024 (UTC)[reply]

Definition in Intro

Heaven forbid we actually reveal the meaning of a word in the introduction. "principal quantum number ... is one of four quantum numbers [of an] electron to describe that electron's state"

That's it? The most important thing about the quantum number n is that it's one of four? That's like saying "Kim Kardashian is one of four children of Kris and George Kardashian". That's not the most important thing about Kim.

Meanwhile, the intro introduces big words I don't even remember from quantum class. And have needless nothing words. I'm changing it to (first draft):

In quantum mechanics, the principal quantum number (n) of an electron tells which electron shell it's in. Its values are natural numbers (1, 2, ...). This number tells the energy level of electrons in that shell (although there's other details).

[that's it - n in a nutshell, without getting into more compex details. Other Details - an applied mag field will tweak these energies - but don't go into it here, their brains might already be overflowing. Now for some examples, connecting to stuff they already know, so these concepts aren't just floating randomly in their brains.]

Hydrogen and Helium, at lowest energy, have just one electron shell. Lithium through Neon (see periodic table) have two shells: two electrons in the first shell, and up to 8 in the second shell. Larger atoms have more shells. [Minimize verbiage: I'm not going to march down the periodic table - if they go toperiodic table, they'll see all that without me going into excruciating detail here. And, I don't need to go into detail about how many electrons in Hydrogen and Helium shells, or others - they can guess or go look it up. That's what those other articles are for; this here is just a big picture.]

It is one of four quantum numbers assigned to each electron in an atom to describe that electron's state. The other quantum numbers for bound electrons are the total angular momentum of the orbit ℓ, the angular momentum in the z direction ℓ_z, and the spin of the electron itself s. [l and m_l have names that are just confusing, I think, azimuth should be m_l or l_z?... avoid them but still point to the article. l_z is the way I was taught - magnetic stuff comes later, although the magnetic issues were discovered first.] OsamaBinLogin (talk) 03:22, 17 February 2025 (UTC)[reply]