Question

for which of the following species bhors model is not valid1) He+2)H(g)3)Li2+4)H+

Answer 1

The Bohr's model is applicable for Hydrogen and hydrogen-like atoms.

Eg: Hydrogen, He⁺, Li²⁺, Be⁺³, etc.

H⁺ is a species which 'cannot' be called Hydrogen atom or hydrogen-like, and hence is not valid in Bohr's model.