Question

The energy required to remove an electron from $n=2$ state in hydrogen will be

• A. $13.6eV$
• B. $3.4eV$
• C. $27.2eV$
• D. $6.8eV$

Answer 1

The correct option is B $3.4eV$

Given: $n=2$
For hydrogen atom the ground state energy is $E_0=-13.6eV$ and Z = 1. The energy of electron in $n^{th}$ state is
$E_n=\frac{E_0\times Z^2}{n^2}$
$E_2=\frac{-13.6\times (1{)}^2}{(2{)}^2}$
$E_2=-3.4eV$
Hence, the energy required to remove an electron from $n=2$ state in hydrogen is $+3.4eV$.