The excitation energy of a hydrogen-like ion in its first excited state is `40.8 eV` Find the energy needed to remove the electron from the ion

Answer

`54.4 eV`

Explanation

`40.8=(Delta E)_(2 to 1)xxZ^(2) rArr 40.8=10.2xxZ^(2) rArr z^(2)=4 "or" Z=2`
`IE=13.6 Z^(2)=13.6xx4=54.4 eV`