Question

Which of the following metals can form nitride with nitrogen ?

• A. $Li$
• B. $Na$
• C. $Mn$
• D. $Ca$

Answer 1

Answer: (A)

$Li$

Lithium is the only alkali metal which combines directly with nitrigen to form lithium nitride.

$L{i}_{\left(s\right)}+N_{2\left(g\right)}⟶2L{i}_3{N}_{\left(s\right)}$

As lithium is the smallest alkali metal, $L{i}^{+}$ will have the highest positive charge density.

As nitride $\left(N^{3-}\right)$ ion is an extremely small highly charged anion, it forms stable ionic compound with cations of high positive charge density, i.e. $L{i}^{+}$.