Nitrogen can form $p \pi-p \pi$ multiple bonds with itself.

$\quad \mathrm{P}\left(\mathrm{C}_2 \mathrm{H}_5\right)_3$ and $\mathrm{As}\left(\mathrm{C}_6 \mathrm{H}_5\right)_3$ form $\mathrm{d} \pi-\mathrm{d} \pi$ bond with transition metals.

Phosphorus, arsenic and antimony show catenation property.

Nitrogen can form $d \pi-p \pi$ bond with oxygen.

Carbon has the ability to form $p \pi-p \pi$ multiple bond with itself.

$\mathrm{ECl}_3(\mathrm{E}=\mathrm{B}$ and Al$)$ is a monomer when $\mathrm{E}=\mathrm{B}$ and a dimer when $\mathrm{E}=\mathrm{Al}$.

The order of catenation property of Group 14 elements is $\mathrm{C} \gg \mathrm{Si}>\mathrm{Ge} \approx \mathrm{Sn}$.

Oxygen exhibits only -2 oxidation state.