Which is higher: the second ionisation energy of sodium or the second ionisation energy of magnesium. Explain.
Mg+ has an electronic configuration of 1s22s22s63s1, Na+ has an electronic configuration of 1s22s22s6
Shielding in both Mg+ is higher than that of Na+.
Effective nuclear pull on the Na+ is much higher than that of Mg+
The Ionisation Energy is much higher for Na+