The electron-pair geometry is easy to determine using the Lewis dot structure. You can tell the shape based on the bonds and the lone pairs around the central atom:
1. SbF3
You have there the Lewis Dot structure of SbF3. Look at the central atom. It has 3 bonds and one lone pair. A lone pair is a pair of electrons that did not bond with other electrons of other groups. You can see the lone pair of SbF3, which is represented by the pair of dots on top of Sb.
If there are three bonds and 1 lone pair, electron geometry of SbF3 is Tetrahedral and the molecular geometry is Trigonal pyramidal.
2. AlCl3
In this molecule, we have Al or aluminum as your central atom. Look around it, do you see pairs of dots around it? No. There are no lone pairs. Instead what you see are 3 lines, those are the bonds or bonding pairs. So you can say that AlCl3 has no lone pairs and 3 bonding pairs.
If there three bonds and 0 lone pairs, the electron-pair geometry of this molecule is Trigonal Planar and the molecular geometry of this is Trigonal Planar as well.
