Here's why:

* Nitrogen has 5 valence electrons. These are the electrons in the outermost shell that participate in bonding.

* To achieve a stable octet (8 electrons in its outer shell), nitrogen needs to gain 3 more electrons.

* Nitrogen forms covalent bonds by sharing its electrons with other atoms. This allows each nitrogen atom to effectively "own" 8 electrons.

Therefore, nitrogen typically forms three covalent bonds to achieve a stable electron configuration. This is why you see nitrogen in compounds like ammonia (NH3) and nitrogen gas (N2).