Which hydrogen -like species will have the same r adius as that of Bohr orbit of hydrogen atom ?

Options

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

Answer

C

Explanation

According to Bohr's theory, the radius of the `nth` orbit of `H`-like species is given as
`r_(n) = (n^(2)r_(1))/(Z)`
where `r_(1)` is the radius of Bohr's orbit of the `H` atom. If `n^(2)=Z`, then `r_(n) = r_(1)`. This is possible only for `Be^(3+) (n = 2)` as the atomic number of `Be^(3+)` is `4`.