The Language of Chemistry — Question 11

Ca₃N₂

Reason — Calcium (Ca) forms a +2 ion (Ca⁺²) and nitride (N^-3) has a –3 charge.

$\text{Ca}^{2+} \space \text{N}^{3-} \\[1em] \overset{\phantom{22}{2}}{\text{Ca}} \space {\swarrow}\mathllap{\searrow} \space \overset{3}{\text{N}} \Rightarrow \underset{\phantom{2}{3}}{\text{Ca}} \space {\swarrow}\mathllap{\searrow} \underset{\phantom{2}{2}}{\text{N}} \\[1em] \text{Ca}_3\text{N}_2$

It is perfectly balanced. Therefore, Ca₃N₂ is correct.