Given:
The ionization potential of hydrogen atom =13.6 eV
We know that,
E(n)=−13.6n2 eV/atom
Here, the electron is to be removed from n=2. Therefore,
ΔE=E(∞)−E(2)
ΔE=0−(−13.622)
ΔE=13.64
ΔE=3.4 eV
Hence, this is the required result.
If 13.6 eV energy is required to ionize the hydrogen atom, then the energy required to remove an electron from n = 2 is