Question

Spin angular momentum in Sodium is __

Answer 1

Hi,

Na = [Ne]3s1. Neon is a closed shell, so you don’t have to worry about the first ten electrons (angular momentum = 0).

One s electron has a spin of 1/2.

Also note:

Total spin angular momentum of Na (spin-spin coupling): S = 1/2.

Spin multiplicity of Na: 2S + 1 = 2 (doublet).

Total orbital angular momentum of Na (orbit-orbit coupling): L = 0 (= “S”).

Total angular momentum of Na (spin-orbit coupling: J = 1/2.

Russell-Saunders term: 2S1/2.

There is only term, so 2S1/2 is also the ground state (lowest energy) term.

I hope this helps.