Atoms question for NEET (NEET 2020), with solution

Answer: (D) Singly ionised neon atom (Ne$^+$)

Bohr's model applies only to hydrogen-like systems, which have a single electron (H, deuterium, He$^+$, Li$^{2+}$, ...).

Singly ionised neon (Ne$^+$) still has 9 electrons, so the model does not apply to it.

Solution by Sreeraj P, M.Sc Physics