#vsper

Valence Shell Electron Pair Repulsion (VSEPER): proposes that the geometric arrangement in a covalent compound, or charged ion, is determined solely by the repulsions between electron pairs present in the valence shell of the central atom. Repulsion causes electron pair to arrange themselves in 3D space to achieve maximal distance.

Steric Number: (Total Number of Atoms) + (Number of Lone Pair).

Cheat: Count the number of atoms attached to the central atom and the number of lone pairs (LP).

Steric Number 4 - Tetrahedral

0 LP - Tetrahedral geometry

1 LP - Trigonal Pyramidal geometry 

2 LP  - Bent geometry

Steric Number 3 - Trigonal Planar

1 LP - Bent Geometry

0 LP - Trigonal Planar