Question

Identify the least stable ion among the following

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Outer electronic configuration of $Li$ - ($2s^2$ most stable)

$Be$ - ( $2s^{2}2p^1$ less stable) than $Be$ ($2s^2$ most stable)

$B$ - ($2s^{2}2p^2$ stable) ; $C$ - ($2s^{2}2p^3$ most stable)

As $Be$ - is formed from highly stable configuration it tries to loose electron and form $Be$.