Which element having the following electronic configuration has minimum ionisation potential?

Options

A. `1s^1`
B. `1s^2, 2s^2 2p^6`
C. `1s^2, 2s^2 2p^6, 3s^1`
D. `1s^2, 2s^2 2p^2`

Answer

C

Explanation

`1s^2 2p^2 2p^6 3s^1`. It belongs to IA group which has least ionisation potential and it decreases down the group.