[Scratch-]

Does the size of an atom change much when it’s heated? Often when an element is heated it excites its electrons and they create light as they fall back to a lower energy level, would this make an atom larger?

[jdurg]

I do not believe that the atomic radius of an atom changes with temperature.  When the electrons are "excited" to a higher energy level, they really aren't moving, so to speak, to a different part of the atom.  They are just gaining more energy and then releasing that energy.  It would be like an employee getting a raise.  They really aren't being 'raised" above anything.  It's just the terminology.  

[Scratch-]

Hmmm... I guess I mistook energy level for electron shell, as my poor memory often does.  

[Donaldson Tan]

huh? I always thought the energy level of the electron is inversely proportional to the distance of it is away from the nucleus. 2p > 2s, so 2p electrons ought to be furthur away from 2s, but the distance shouldn't be significantly far apart, cuz they are in the same shell.

pls enlighten~

[Mitch]

I think geodome is right on this one.

[jdurg]

I think geodome is right on this one.

Quite possibly he is.  (Haven't had a quantum mechanics course in a few years.  )  I just thought that the electrons remained in their original shells, but just gained energy.  Since the higher energy electrons don't belong in the shell they are in, they release that energy in the form of light.  At least that's what my brain remembers.  

[WARRAVEN]

Geodome is partly correct. I am assuming we all know that an atom's orbital is not a circle, but a grey are of which it is probable of being as it jumps around. The diference between the 2s and 2p orbitals is not wholly distance, but shape. The shape of the p orbital is a dumbell shape while the shape of the s orbital is that of a sphere. The reason that the p orbital is considered mostly farther away is that parts of the dumbell go farther away than the sphere. The hardest part after learning all the quantum theory and spaces, orbitals electrons is probably that all these shells are overlapping, all the 2 sub-orbitals are stacked pretty much ontop one another(of course not all in one exact spot, but you can imagine what I mean, while the other orbitals s,p,d,and f are slightly farther away they are very close to being in the same general area, which is why they are SUB-orbitals).
Its very hard to imagine, and unless you are specifically asked whether or not they overlap and are together like this it is probably best to think of them as you are, seperate and apart. And what I can picture of an electron is that it absorbs the energy, gets excited, and throws it back up because it cannot remain at that state, so it spits it back up(nice picture,lol) as a photon of light.
Thinking thats the general question you asked, but the atom composition and identity does not change(as that to change an element to another you must change the amount of protons, not e- ), the size also remains the same as that the electrons activity is so quick that it seems to just give off the photon(As we can tell) and by itself it doesn't change the atom(however the decompisition of hydrogen peroxide comes to mind, that if exposed to light it will decompose, which is why it is in the bottle). I hope I answered your question, I still have a lot to learn but thats somewhat answering your question.

          Raven  :devil1:

[Mitch]

Wow, okay I can see we are taking this question to a more advance level now. Warraven is generally correct when he speaks of atoms absorbing photons. Just remember that there is a distinct difference between when an atom versus a molecule absorbs a photon. For instance the chemical reactivity of a molecule after it absorbs a photon is completely different than before it absorbed the photon.

Perhaps we should add a Photochemistry Forum

[gregpawin]

Atomic radius??? that's so classical.  Actually, that atom can jump from my lab and appear in my face as I type this.  Are you talking about 97% of the time?  100%, well that's between the atom and infinity.

Its also interesting to note that the production of photons due to excitation involves knowledge based on quantum field theory.

[Mitch]

not neccessarily. Photons are just given when the atom falls from an excited vibration state to a lower vibration state. Which would be floresence if its singlet to triplet or phosphoresence if its from triplet to singlet, its actually all old quantum mechanics.

[gregpawin]

But the creation of new particles in space is governed by QFT... this is what the professor said anyways.

[Mitch]

I guess, but very simple quantum mechanics is needed to fully predict any of the observed photons. I've been reading heavily into Photochemistry.