The radius of which of the following orbit is same as that of the first Bohr's orbit of hydrogen atom.

Options

A. ` He^(+) (n =3)`
B. `Le^(2+) ( n= 2)`
C. `Li^(2+) ( n=3)`
D. `Be^(3+) ( n=2)`

Answer

D

Explanation

` r_2 Be^(3+) = (r_2 H)/Z= (r_1 Hxx 2^2 )/ = ( r_1 H xx 4)/4`.