Out of Na and Mg , which has higher second ionisation energy?

Explanation

`Na-1s^(2)2s^(s)2p^(6)3s^(1)`
Mg - `-1s^(2)2s^(2)2p^(6)3s^(2)`
Second ionisation energy of Na is higher because it acquires nearest noble gas configuration after losing one electron and 2nd electron is to be removed from the noble gas configuration.