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Electron orbital jump

  1. Nov 16, 2004 #1
    Alright, I have a question regarding quantum physics, but I don't want to post in that forum, because it scares me. I saw a website, it had an atom fill up electrons in orbital, as it got high, a rather unusual thing happened, an electron from an S orbital jumped to fill a P sub-orbital. I was wondering why this happens.
     
  2. jcsd
  3. Nov 17, 2004 #2
    If the atom were to be the only one in the universe this would not have happened. Simply the s-electron would not jump to a sub p orbital. But an atom is contantly puturbed means constantly there is a "push" here and there.
    So the atom wants to go to the state in which it is stable. So the phenomenon occurs.
     
  4. Nov 17, 2004 #3

    ZapperZ

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    Your description is vague. Was this transition (from S to P) occuring WITHIN the same principle quantum level n?

    If we are talking about the regular transition that occurs between different n levels, then the transition from "an S orbital to a P orbital" via the emission of a photon is due to a selection rule, or more precisely, the dipole selection rule. Describing it in words, there are two broad "rules" for such a transition:

    (i) it must be between different n levels (example: the Balmer series)
    (ii) it must be between orbital levels that is different by 1 angular momentum quantum number (i.e. s to p, p to s, p to d, etc... but NOT s to d)

    This selection rule comes out naturally if you work out the dipole matrix element using the atomic wavefunction as the basis functions, i.e. it wasn't just made up out of thin air. It also a result of conservation laws, since the emission of a photon "creates" a particle with angular momentum of 1. Thus, the atom making that transition must also undergo a change in its angular momentum to preserve this conservation law.

    Zz.
     
  5. Nov 17, 2004 #4
    No, that's not what I'm talking about Zapperz, this is.
    http://lectureonline.cl.msu.edu/~mmp/period/electron.htm
    This is a website that shows how electrons would configure in an atom.
    I'm correcting myself, not a P orbital, but a D orbital. The electron jumps from a filled S orbital to a D orbital. I wanted to know why.
     
  6. Nov 17, 2004 #5

    ZapperZ

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    Next time, it helps if you show the site where you're reading all these things. Both santoshroy and I interpreted what you wrote as being an atomic transition! The LAST thing you want to do is annoy the people who put in the effort and time trying to answer your question. And I do get annoyed for spending time for nothing in responding to this.

    The filling of the 4d orbital ahead of the 3d is primarily due to the closeness of the average position of the 4d electron when compared to the 3d orbital. This gives a lower energy state for the 4d. There are other more complicated answers for this which I no longer have the patience to go through.

    Zz.
     
  7. Nov 17, 2004 #6
    Well, your schedule can't be that tight, considering you responded to my post in less than an hour. Anyone else?
     
    Last edited: Nov 17, 2004
  8. Nov 17, 2004 #7

    ZapperZ

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    You're welcome. It's nice to know our efforts are so "appreciated".

    Zz.
     
  9. Nov 17, 2004 #8
    Hey, you're the one who got impatient over two posts. You're efforts are "appreciated", but you don't want to ellaborate, so I'll look for a more descriptive reply.
     
  10. Nov 17, 2004 #9
    I think I might get it, the 4s orbital has a lower energy state than the 3d orbital. It fills first, but, as the 3d orbital is filling, it steals an electron from the 4s - wait a minute, it steals it to get to 5, that doesn't make sense.
    Now I'm confused.
    Edit - Ahah, now I got it. After doing a google search, I found out that more unpaired spins means a lower overall energy. That's why it jumps, but wait a minute how can more unpaired spins mean a lower overall energy?
    http://antoine.frostburg.edu/chem/senese/101/electrons/faq/4s-3d.shtml
     
    Last edited: Nov 17, 2004
  11. Nov 21, 2004 #10
    Anyone have an answer?
     
  12. Nov 21, 2004 #11
    When electrons get paired up, they are put in very similar spatial wavefunctions, which results in increased repulsion since they are both negatively charged. Different spatial wavefunctions are generally orthogonal, or in any event the overlap is much smaller. So if you are working with a number of states of approximately equal energy and fill them up with electrons, the electrons will first go to a completely empty state and only then go to states that are half-filled. I believe this is called Hund's rule.

    Building up atoms by filling the p orbitals is a prime example. See http://www.webelements.com/webelements/properties/text/image-period-2sp/ionization-energy-1.html : note the ionization energy generally increases since the nucleus becomes more positive and the electrons with the same n do not shield each other. However, watch the decrease from nitrogen to oxygen: this is b/c in nitrogen the p orbitals are each half full, whereas oxygen's extra electron goes into another p orbital and the resulting repulsion actually wins out over the nuclear charge increase.
     
  13. Nov 21, 2004 #12

    Gokul43201

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    See Hund's Rule. Pairing electrons increases electron-electron interaction.
     
  14. Nov 22, 2004 #13

    t!m

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    Long story short, orbitals are most stable when full, and second most stable when half-full. Some atoms will sacrifice a full Xs2 orbital and take away one electron, leaving a half-full Xs1 orbital. This electron will either be used to make an Xd4 into an Xd5 (now half-full and thus more stable), or an Xd9 into an Xd10 (now completely full and thus most stable).
     
    Last edited: Nov 22, 2004
  15. Nov 23, 2004 #14
    Alright, thank you. Why are orbitals more stable when full or half full?
     
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