The representative particle of nitrogen gas is a diatomic molecule, specifically N₂.

Here's why:

* Nitrogen exists naturally as a gas. This means nitrogen atoms bond together to form molecules.

* Nitrogen is diatomic. This means each nitrogen molecule consists of two nitrogen atoms bonded together.

* The chemical formula for nitrogen gas is N₂. This formula represents the diatomic molecule.

So, the representative particle of nitrogen gas is the N₂ molecule.