Polarity of molecules can be explained with Lewis Dot Structures.
Molecules form when atomic orbitals overlap and form bonds.
Need to hybridize these atomic orbitals to get the correct geometries and shapes. The VB-theory accounts for shapes of molecules but not their energies. Then throw the electrons into this molecular energy level diagram. In this theory electrons and the orbitals in which they are found are considered to belong to molecules not the atoms. Formation of bonding and antibonding MO's.