1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Quantum Numbers

  1. Jun 18, 2012 #1
    1. The problem statement, all variables and given/known data

    Lithium has an atomic number Z = 3. Two of its electrons have the quantum numbers {n, L, m{l}, m{s}} = {1,0,0,+1/2} and {1,0,0,-1/2}. Write down the corresponding set of quantum numbers for the third electron in the lowest energy state of the Li atom. Briefly explain the factors motivating the set of quantum numbers

    2. Relevant equations

    3. The attempt at a solution

    Haven't done quantum numbers in a while.

    The first shell is full so n=2. It is Lithium so it is still in the s orbital so l = 0
    Firstly is this correct?

    Now is where I get a little confused. Do the electrons have a preference when it comes to the m{s} numbers? Does it prefer to fill m{s} +1/2 before -1/2

    My final answer for this question is (2,0,0,+1/2) is this correct?

    Thank you for your time.
    Last edited: Jun 18, 2012
  2. jcsd
  3. Jun 29, 2012 #2
    n=2, L=m(l)=0 should be correct for the reasons you have outlined above.
    If you are being asked for the corresponding Set(!) of quantum numbers I believe you want to include both the spin-up and spin-down states in your answer.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook