The most stable ion of nitrogen is the nitride ion, which carries a charge of -3.
Nitrogen has five valence electrons in its outer shell and needs three additional electrons to achieve a stable octet configuration. When nitrogen gains three electrons, it forms the nitride ion (N3-), resulting in a stable energy state. This -3 charge signifies that it has three more electrons than protons, leading to its stability as an anion.
In various compounds and reactions, nitrogen can also exist in other ionic forms, but the nitride ion is the most stable in terms of its electron configuration and energy. In summary, the nitride ion, with a charge of -3, is the most stable ionic form of nitrogen, reflecting its ability to attain a full outer shell of electrons.