Question

How many bonding orbitals are there in `PCl_3`?

Answer 1

`PCl_3` has three bonding orbitals.

There is a total of 26 valence electrons in this molecule, 5 on `P` and 7 on each `Cl` atom. Three of the `sp^3` hybrid orbitals on `P` overlap with one `p` orbital on each `Cl` atom to form three bonding orbitals (occupied) and three anti-bonding orbitals (unoccupied).

The fourth `sp^3` hybrid orbital on `P` is a doubly occupied non-bonding orbital, as are the remaining `p` orbitals on the three `Cl` atoms.