# The radius of the second Bohr orbit, in terms of the Bohr radius,

Question:

The radius of the second Bohr orbit, in terms of the Bohr radius, $a_{0}$, in $\mathrm{Li}^{2+}$ is:

1. $\frac{2 a_{0}}{3}$

2. $\frac{4 a_{0}}{9}$

3. $\frac{4 a_{0}}{3}$

4. $\frac{2 a_{0}}{9}$

Correct Option: , 3

Solution:

$r=\frac{a_{0} n^{2}}{\mathrm{Z}}$

For $\mathrm{Li}^{2+}, r=\frac{a_{0}(2)^{2}}{3}=\frac{4 a_{0}}{3}$