Question

Not considering the electronic spin, the degeneracy of the second excited state (n = 3) of H atom is 9, while the degeneracy of the second excited state of H– is

Answer 1

Energy order of orbitals of H is decided by only principle quantum number (n) while energy order of H– is decided by (n + l) rule: Electronic configuration of 'H–' is – 1s2 its Energy order is decided by n+ rule.

H=1s² 2s⁰ 2p⁰

Its 2^nd excited state is 2p
and degenery 2p is ‘3’