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Homework Help: Spectroscopic/term symbol atomic physics question

  1. May 16, 2008 #1
    Sodium, = 11, has the ground state configuration [Ne] 3s^1 and is a “one
    electron” atom. Magnesium, Z= 12, is a “two-electron” atom. Write down its
    ground state configuration and possible term values.

    i think i get the right answer but im having a couple of issues:

    my answer:

    ground state configuration: [Ne] 3s^2

    possible term values are for the spin multiplicity either S = 1 or 0 so 2S+1 = 3 or 1

    L = 0 therefore = 0

    therefore J = 1 or 3

    however im inclined to go with J = 1 as i think the exclusion plays a role.

    p.s. ill happily clarify anything here as i know its not the clearest, i just dont know how to wrie term/spectroscopic notation in latex/html


    i just find this term symbol stuff abit cinfusing
  2. jcsd
  3. May 17, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    No, your J - value is wrong.

    Tell me, what is the formula for adding two angular momentums in quantum mechanics. i.e What is the formula for J in this case?

    This is the way to write a Term:

    [tex] ^{2S+1}L_J [/tex]

    Just click on this image to see the Tex-code, you should figure out how to chage the code to fit your needs-

    Also, this is wrong:

    "ground state configuration: [Ne] 3s^2"
    We were discussing Mg right?
  4. May 22, 2008 #3

    its ok i spoke to a chemist and he set me straight. besides, ive already had that exam, so i can set about forgetting everything i learnt ;)
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