???
Hahajaja?

Thanks mam and you are elder so plz dont be sorry
It can be defined as the electrons which are there in degenerate orbitals have a parallel spin and tend to exchange their position. The exchange energy is the energy released when two or more electrons with the same spin-exchange their positions in the degenerate orbitals of a subshell. Exchange energy is nothing but the energy released during this process. When the orbitals are half-filled or completely filled then the number of exchanges is maximum. Therefore, its stability is maximum.