Which orbit of `Be^(3+)` has almost same radius as that of the ground state of H-atom?

Options

A. Second
B. Third
C. Fourth
D. Sixth

Answer

A

Explanation

`r_(n)=(0.059n^(2))/Z`
`r_(1)=(0.059xx1^(2)=0.059`
`r_(n)(Be^(3+))=(0.059xxn^(2))/4=0.059 " " ( :. Z=4)`
` n^(2)=4 `or `n=2`