Question

The 2nd separation energy of Li2+ will be :
(1) 54.4 eV
(2) 13.6 eV
(3) 48.3 eV
(4) 122.4 eV​

Answer 1

Separation energy is the energy required to separate a particle from the nucleus of an atom. Generally it applies to protons and neutrons. However, it can apply to electrons as well.

In case of electrons, separation “energy is the minimum” amount of energy required to remove an electron from its excited state. “According to Bohr's Model”, the separation energy of an electron in any shell of “Hydrogen atom is given” by  where n is the number of the orbit.

So for the 1st orbit or shell, the separation energy would be -13.6ev. In the second energy level, which is the first excited state, the separation energy would be  

. So, the second separation energy of Hydrogen atom would be -3.4 ev.

SO THE FINAL ANSWER IS 13.6 eV