Question

How can electrons absorb energy and then give it off in chemical reactions?

Answer 1

First, when the reaction start , electron absorb energy by jumping from lower energy to higher energy level. In higher energy level , electron is in excited state and thus the corresponding compound have higher energy. In simple words I would say the stability of compound decreases and now the compound is reactive due to excitation of electron from lower energy level to higher energy level by absorbing energy.

This reactive compound will again try to achieve stability. In order to do so , the compound will react with another molecule to form bond (ionic, covalent or coordinate bond). During formation of bond, the excited electron jumps back from higher energy level to lower energy levels by loosing energy to form . Simply we could say that the excited electron get involve in bond formation to lower it's energy and while lowering it's energy , electron give off it's energy.