[Haryana PMT 2010] The electronic configuration 1s², 2s², 2p¹ₓ 2p¹ᵧ 2p¹_z for nitrogen (not 1s², 2s², 2p²ₓ 2p¹ᵧ 2p⁰_z) is determined by

Hund's rule of maximum multiplicity: electrons enter degenerate orbitals singly before pairing. So N has one electron each in all three 2p orbitals.