Question

The ion which is isoelectronic with $CO$ is

• A. $C{N}^{-}$
• B. $O_2^{+}$
• C. $O_2^{-}$
• D. $N_2^{+}$

Answer 1

The correct option is A $C{N}^{-}$

$C{O}^{-}$ - has $14$ electrons $(6+8)$.
$C{N}^{-}$ -has $14$ electrons $(6+7+1)$.
$O_2^{+}$ -has $15$ electrons $(8+8-1)$.
$O_2^{-}$ -has $17$ electrons $(8+8+1)$.
$N_2^{+}$ -has $13$ electrons $(7+7-1)$.