Optical Spectra of Helium & Other Elements

[w3390]

Homework Statement

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.

Homework Equations

N/A

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.

 

[Bohrok]

I'd say lithium because it has only one more electron than helium, but I'm not too sure about spectra problems.

 

[Borek]

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.

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methods

 

[w3390]

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.

 

[Borek]

s¹ sounds more hydrogenish

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