Question

By examining electron domain geometry, one can determine that the ammonia molecule (NH3) has
one sp2 orbital.
two sp2 orbitals.
three sp3 orbitals.
four sp3 orbitals.

Answer 1

Four sp3 orbitals.

Reason: N in NH3 has 3 bonds + 1 lone pair = 4 electron domains → tetrahedral electron-domain geometry → sp3 hybridization (four sp3 orbitals: three used for N–H bonds, one holds the lone pair).