Question

Which one of the following molecules is paramagnetic?

• A. $N_2$
• B. $NO$
• C. $CO$
• D. $O_3$

Answer 1

Answer: (B)

$NO$

A molecule with one or more unpaired electrons is paramagnetic or odd electron system is paramagnetic. $NO$ has 15 electrons and has a bond order of $2.5$ and has 1 unpaired electron in ${\pi }^{\ast }$ antibonding orbitals. So, $NO$ is a paramagnetic molecule.