Final answer:
Electron geometry refers to the arrangement of electron pairs around a central atom, while molecular geometry describes the arrangement of atoms in a molecule. The key factor that distinguishes molecular geometry from electron geometry is the bond angle.
Step-by-step explanation:
Electron geometry refers to the arrangement of electron pairs around a central atom, including both bonded pairs and lone pairs. Molecular geometry, on the other hand, describes the arrangement of atoms in a molecule, excluding the lone pair electrons. A key factor that distinguishes molecular geometry from electron geometry is the bond angle. The bond angle is the angle between any two bonds that include a common atom. It helps to determine the overall shape of the molecule.