In the 2D 5/2, we can extract from the notation that S=0.5, L=2 and J=5/2, so using the formula, and considering gl=1 and gs=2, the g factor of the atom becomes gj=1.2
In the 2D 3/2, we can extract from the notation that S=0.5, L=2 and J=3/2, so using the formula, and considering gl=1 and gs=2, the g factor of the atom becomes gj=0.8
I don’t know the difference in calculating for the ground state. I guess the ground state is 2D 3/2, so the g factor of this state has been already calculated and should be gj=0.8.