Nitrogen has an atomic number of 7, meaning it has 7 protons and 7 electrons. Its electron configuration is 1s²2s²2p³. To achieve a noble gas configuration, nitrogen needs to gain three electrons to have the same electron configuration as neon (1s²2s²2p⁶).

Therefore, nitrogen will have a -3 charge to achieve a noble gas configuration. This is why nitrogen typically forms compounds with a -3 oxidation state.