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Homework Help: Optical Spectra

  1. Oct 20, 2009 #1
    1. The problem statement, all variables and given/known data

    The following elements should have optical spectra similar to either a hydrogen atom or a helium atom. Indicate which of the following elements should have optical spectra similar to a helium atom. (Select all that apply.)

    The choices are: Cadmium, Lithium, Technetium, Titanium, Platinum, Strontium, Calcium, and Francium.

    2. Relevant equations


    3. The attempt at a solution

    I thought that since helium has a full level of valence electrons, it would have similar optical spectra as other elements with their highest orbitals completely filled. So I went with Strontium and Calcium, but this is incorrect. What am I doing wrong? Any help would be much appreciated.
  2. jcsd
  3. Oct 20, 2009 #2
    I'd say lithium because it has only one more electron than helium, but I'm not too sure about spectra problems.
  4. Oct 21, 2009 #3


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    Staff: Mentor

    I don't like the question. My guess would be to go for s2 atoms with all other orbitals filled.

    Somehow I don't think this approach will survive when comparing real spectra.

  5. Oct 21, 2009 #4
    Ya, that's what I thought too, so I chose Strontium and Calcium but I am wrong. Do you think I should include 1s atoms as well that have all other orbitals filled? I haven't yet tried the combination: Lithium, Calcium, Strontium, and Francium. This may be it, but I am hesitant because I only have one chance left on my assignment.
  6. Oct 22, 2009 #5


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    Staff: Mentor

    s1 sounds more hydrogenish :wink:

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