Question

The ion that is isoelectronic with $CO$ is

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

Answer 1

Answer: (C)

Isoelectronic species are those species, which have same number of electrons.
Total number of electrons in $CO$ is $=6+8=14$
(a) Total number of electrons in $O_2^{+}$ is $=8+8-1=15$
(b) Total number of electrons in $C{N}^{-}$ is $=6+7+1=14$
(c) Total number of electrons in $O_2^{-}$ is $=8+8+1=17$
(d) Total number of electrons in $N_2^{+}$ is $=7+7-1=13$
Thus, $C{N}^{-}$ is isoelectronic with $CO$.