Final answer:
In the azide ion, the central nitrogen forms one sigma bond and two pi bonds, resulting from sp hybridization and the linear arrangement of nitrogen atoms.
Step-by-step explanation:
The azide ion (N3−) consists of a linear arrangement of nitrogen atoms. The central nitrogen atom forms one σ bond (sigma bond) with one of the adjacent nitrogen atoms, and it forms two π bonds (pi bonds) with the other adjacent nitrogen atom as part of a triple bond. This bond structure is due to the sp hybridization of the central nitrogen atom where one sp hybrid orbital forms the sigma bond, and the remaining unhybridized p-orbitals form the pi bonds.