Question

Identify the least stable ion among the following.

• A. $L{i}^{-}$
• B. $B{e}^{-}$
• C. $B^{-}$
• D. $C^{-}$

Answer 1

The correct option is B

$B{e}^{-}$

Here we are going to compare these with each other and find out which is the least stable. But these species might not exist due to inherent instability.

Electronic configuration of $L{i}^{-}$ - ($2$) fully-filled, so relatively more stable.

$B{e}^{-}$ - ($2,1$) less stable than $Be$ ($2$);

$B^{-}$ - ($2,2$) relatively stable;

$C^{-}$ - ($2,3$) relatively stable.