Answer
$1s^{2}2s^{2}2p^{6}$ = 2080 kJ/mol.
$1s^{2}2s^{2}2p^{6}3s^{1}$ = 496 kJ/mol.
Work Step by Step
The element with electronic configuration $1s^{2}2s^{2}2p^{6}$ has an ionization energy value of 2080 kJ/mol. This is due to the stable inert gas configuration of the element. It has a stable octet configuration; that is why it possesses a high ionization energy value.
The element with electronic configuration $1s^{2}2s^{2}2p^{6}3s^{1}$ has an ionization energy value of 496 kJ/mol. It has an incomplete octet configuration; that is why it possesses a low ionization energy value. By the removal of one electron from 3s orbital it attains inert gas configuration.
