Question

Pickout among the following:
Ll${}^{-}$, Be${}^{-}$, C${}^{-}$, species which is least stable?

Answer 1

$Li⟶1s^{1}2s^1$ $B{e}^{-}$ is highly unstable as $Be$ is having completely filled orbital and to add a new $e^{-}$

$Be⟶1s^{2}2s^2$ it will be difficult because it is present in its' highly stable rate.

$C⟶1s^{2}2s^{2}2p^2$