Here's why:
* Nitrogen's electron configuration: Nitrogen has 5 electrons in its outer shell. To achieve a stable octet (8 electrons) like noble gases, it needs to gain 3 electrons.
* Ion formation: Gaining electrons results in a negative charge. Therefore, nitrogen forms a nitride ion (N³⁻).
It's important to note that nitrogen can also form positive ions (cations) in rare circumstances, such as when bonding with very electronegative elements like oxygen. However, its most common ionic form is the nitride ion.
