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Homework Help: Energy of the atomic orbitals!

  1. Jan 6, 2012 #1
    1. The problem statement, all variables and given/known data
    Compare the energies of the 1s, 2s, 3s and 3p orbitals for both the HE and He+. For He assume that one electron is always in the 1s orbital. State any other assumptions you have made

    2. The attempt at a solution
    I think:
    He can be either 1s1 2s1 or 1s2
    He+ has to be 1s1.

    For He 1s2, the 1s orbital has a lower energy than in the case of He+ and since there is a greater shielding, this allows the 2s, 3s and 3p to rise in energy. Hence these have a higher energy than in He+.

    For He1s1 2s1 is basically the same thing, only that now 1s1 has a higher energy than 1s2 but still lower than He+ and 2s1 has a lower energy than in the other cases.

  2. jcsd
  3. Jan 7, 2012 #2

    Simon Bridge

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    Homework Helper

    In He+, you have 2 protons attracting one electron.
    Does this mean that the electron is more or less tightly bound to the nucleus?
    Is "tightly bound" a lower or a higher energy?

    If you are just using a shielding model, then isn't He going to be basically like hydrogen?

    (Does your model include spin-orbit coupling?)
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