Nitrogen exist as a _____________ at room temperature. Monoatomic gas Diatomic gas Triatomic gas None...

The nitrogen atom is a tiny particle and has the tendency to form pπ−pπ multiple bonds. The triple bond between the nitrogen atoms in the N_2 molecule really has a very high thermodynamic stability. It has a 942kJ.mol^-1 dissociation energy. This causes nitrogen to exist at room temperature as a diatomic gas. Additionally, the N≡N is non-polar due to its improved stability, which results in weak Van der Waals interactions between the molecules. The fact that nitrogen is a gas at room temperature is due to this. These factors also render the N_2 molecule very inert at standard pressure and temperature (s).
So, answer is Diatomic gas.