Final answer:
The name for the N₃- ion is the nitride ion. Nitrogen gains three electrons to become a nitride ion, which combines with metals like aluminum to form neutral compounds, like aluminum nitride (AlN).
Step-by-step explanation:
The correct name for the N₃- ion is the nitride ion. In chemistry, when naming a monatomic anion, the standard protocol is to take the stem of the element name, in this case, 'nitr', and append the suffix '-ide' to it, which leads to the name nitride ion. As for its formation, nitrogen is positioned in group 15 of the periodic table, indicating that it is a nonmetal. Nonmetals tend to gain electrons to achieve a full valence shell, similar to that of the nearest noble gas.
In nitrogen's case, it gains three electrons to achieve the same electron configuration as neon, the nearest noble gas, resulting in the formation of a N₃- ion which is called a nitride ion. In an ionic compound, such as aluminum nitride, the aluminum ion (Al³+) and the nitride ion combine in a 1:1 ratio to yield AlN, reflecting the necessity for the compound to have an overall neutral charge.