Final answer:
Electron pair geometry refers to the arrangement of all electron pairs, while molecular geometry only considers the arrangement of atoms in a molecule.
Step-by-step explanation:
The difference between electron pair geometry and molecular geometry lies in their focus. Electron pair geometry refers to the arrangement of all electron pairs, including both bonding pairs and lone pairs, around the central atom. On the other hand, molecular geometry only considers the arrangement of atoms in a molecule, excluding the lone pairs. The electron pair geometry will be the same as the molecular structure when there are no lone pairs, but they will be different when there are lone pairs present.