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Homework Help: Simple question about total angular momentum in an atom

  1. Apr 23, 2007 #1
    1. The problem statement, all variables and given/known data
    Consider the 6g state of an electron in a hydrogen atom.

    Enter the smallest possible value of the total angular momentum quantum number.

    2. Relevant equations
    hund's rules:
    1. the total spin angular momentum S should be maximized to the extent possible without violating the Pauli exclusion principle.
    2. Insofar as rule 1 is not violated, L should also be maximized.
    3. For atoms having subshells less than half full, J should be minimized.

    j=l (+ or -) s

    l=4 (for g)

    3. The attempt at a solution

    I know this is a simple question but i can't seem to comprehend spin very well. I suppose my biggest problem is that i don't know what "s" (spin angular momentum) is and i don't know how to find it out. is it just 1/2 since it's a hydrogen atom?

    if that's the case it seems like we need to maximize both l and s, so
    j_min=l-s=4-1/2 but if i recall correctly the answers on the multiple choice test were integers (this question is for test corrections)

    i can't seem to find out very much information in either my physics book or online sources (wikipedia, etc.) so if someone could point me in the right direction i'd really appreciate it.
  2. jcsd
  3. Apr 24, 2007 #2

    Meir Achuz

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    Gold Member

    If this is the question, then the answer is simple.
    g means L=4. The electron has spin 1/2, so the minimum J is 4-1/2=7/2.
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