Question

lf the binding energy of the electron in a hydrogen atom is 13.6 $eV$, the energy required to remove the electron from the first excited state of $L{i}^{2+}$ is:

• A. 30.6 eV
• B. 13.6 eV
• C. 3.4 eV
• D. 122.4 eV.

Answer 1

The correct option is A 30.6 eV

The energy of the first excited state of $L{i}^{++}$ is$E_2=-\frac{Z^2{E}_0}{n^2}=-\frac{3^2\times 13.6}{2^2}=-30.6eV$.
The energy need to be given to remove the electron from the first excited state is 30.6 eV.
Option A is correct.