Question

What is the electron separation energy (in $eV$) for $B{e}^{3+}$ in the first excited state.

• A. $13.6eV$
• B. $27.2eV$
• C. $40.8eV$
• D. $54.4eV$

Answer 1

The correct option is D $54.4eV$

Electron separation energy is similar to ionization energy.
For $B{e}^{3+},E_{\infty }-E_2=+13.6\frac{z^2}{n^2}$
$=13.6\times \frac{4^2}{2^2}=54.4eV$