If 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 Li + + is :

Step-by-step solution

Energy of an electron in n th orbit of an ion with atomic number z is, E = - 13 .6 × z 2 n 2   eV for 1 st excited state of L i + + ,   z = 3 ,   n = 2 E = - 13 .6 × 3 2 n 2 = - 13 .6 × 9 4   eV =   - 30 .6   eV ∴ Required energy = 30 . 6   eV