The IE2 of Mg is higher than that of Na. On the other hand, the IE2 of Na is much higher than that of Mg. Explain,
The first electron in both cases has to be removed from the 3s orbital, but the nuclear charge of Na is less than that of Mg. After the removal of the first electron from Na, the electronic configuration of Na+ is 1s2, 2s2 2p6, i.e., that of noble gas which is very stable and the removal of the 2nd electron is very difficult. In the case of Mg after the removal of the first electron, the electronic configuration of Mg+ is 1s2, 2s2 2p6 3s. The 2nd electron to be removed is again from 3s orbital which is easier.
