`IE_2` values of alkaline earth metals are much smaller than those of alkali metals. Explain.

Explanation

`IE_(1)` of alkaline earth metals gt `IE_(2)` of alkali metals.
(ii) `IE_(2)` of alkaline earth metals lt IE, of alkali metals.
(iii) This occurs because in alkali metals the second electron is to be removed from a which has already acquired a noble gas configuration.
(iv) In the case of alkaline earth metals, the second electron is to be removed from a monoval cation, which still has one electron in the outermost shell.
(v) Thus, the second electron can be removed more easily in the case of group 2 elements than in group 1 elements.