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Homework Help: Basic chem. atoms and their electrons.

  1. Jul 28, 2011 #1
    This question is pretty straightforward, but I just can't seem to find the answer..

    What is the reason that electrons only exist in shells and never between them?

    A hint that was given to me was to "think about quantum energy".

    I was thinking because if they wouldn't exist in shells, then everything would be disorganized, they wouldn't be able to combine with other ones that easily, etc, but it just doesn't seem to directly answer the question..
  2. jcsd
  3. Jul 28, 2011 #2
    Is that an exact quote of the question? "What is the reason that electrons only exist in shells and never between them?" If so, it's a terrible question. I would say that electrons DO exist between shells.
  4. Jul 28, 2011 #3
    That is the exact quote, word for word. I don't really know how to answer it though.. And why do you say that?
  5. Jul 28, 2011 #4
    In atoms that have more than one electron, the "shells" get mixed, so that the actual state of an electron doesn't correspond in a clean way with a single shell. Even in a hydrogen atom, an electron can exist in a mixture (usually called a superposition) of two shells.

    I think you're taking an elementary class and the teacher doesn't want to get into stuff like that. But I honestly don't know what he/she is looking for for an answer to "What is the reason that electrons only exist in shells and never between them?"
  6. Jul 28, 2011 #5
    I'm taking an AP class.. This is just part of the summer work that I have to do.. I haven't even met my teacher yet, I'm sure he'll explain it though.
  7. Jul 30, 2011 #6
    eh pmsrw...you must be going to very high level chemistry...normally no electrons don't exist between shells. One of the basics of quantum mechanics is that electrons can only absorb and release energy in certain amounts. They can only exist at certain energies not between them since energy is quantized. Think about it like a staircase, as you are going up the stairs can you stand between one stair step and another (don't try please). The levels that the steps exist at are quantized much like energy in atoms.

    Your explanation doesn't make much sense to me pmsrw3 even using what I know from physical chemistry. Love to see some sources for that explanation. The above is who I explain it and the question as asked above is one I ask on tests every year.
  8. Jul 31, 2011 #7
    As I said above, an electron, or any other particle, can exist in a superposition of states. This is a fundamental characteristic of quantum mechanics.

    No, this is incorrect. It is incorrect to say that this is "one of the basics of quantum mechanics". And the statement "electrons can only absorb and release energy in certain amounts" is also false. I think you are thinking of atoms, not electrons, although the statement is not even entirely true of atoms. For instance, the amount of energy an H atom can absorb is quantized up to the binding energy, but it can absorb any amount above the binding energy -- only the bound states are quantized.

    I think you don't entirely understand what it means to say that energy is quantized. The states you are talking about are the eigenstates of energy. These are the states that have a single definite energy. But those are not the only states. Neither an electron nor an atom necessarily has a definite energy. There are also states in which the particle has more than one energy level.

    Any college-level quantum mechanics textbook.

    I'm sorry to hear that.
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