Question

Which of the following elements do not belong to group IIA or second group?

• A. Be
• B. Mg
• C. Li
• D. Ca

Answer 1

The correct option is C

Li

Explanation for Correct option:

C)Li is an alkali metal with electronic configuration - $1s^{2}2s^1$- It has 1 valence electron, since number of valence electrons is equal to group number.

Li belongs to IA group.

Explanation for Incorrect options:

A)Be is an alkaline earth metal with electronic configuration-$1s^{2}2s^2$- It has 2 valence electrons

B)Mg is an alkaline earth metal with electronic configuration-$1s^{2}2s^{2}2p^{6}3s^2$ -It has 2 valence electrons

D)Ca is an alkaline earth metal with electronic configuration-$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^2$-It has 2 valence electrons

Be,Mg,Ca belong to IIA group.

Hence,C) is the correct option-Li does not belong to IIA group.