The enegry level diagram for an hydrogen-like atom is shown in the figure. The radius of its first Bohr orbit is

Options

A. `0.265 Å`
B. `0.53 Å`
C. `0.132 Å`
D. None of these

Answer

A

Explanation

We know that `E_(n)=- 13.6(Z^(2))/(n^(2))eV` and `r_(n) =0.53(n^(2))/(Z) (Å)`
Here for `n = 1, E_(1) =- 54.4 eV`
Therefore `-54.4 =- 13.6 (Z^(2))/(1^(1)) rArr Z = 2`