VSEPR (Valence Shell Electron Pair Repulsion) theory is a model used in chemistry to predict the shape of molecules. According to this theory electron pairs around a central atom will repel each other and arrange themselves as far apart as possible to minimize repulsion, determining the molecular geometry.

Lone pairs are localized closer to the central atom than bonding pairs, which are shared between two atoms. This closer proximity causes lone pairs to exert more repulsive force on other electron pairs, leading to greater distortion in molecular shape.

VSEPR theory predicts molecular shape by counting the number of electron pairs (both bonding and lone pairs) around the central atom. The arrangement of these pairs is determined by minimizing repulsion, leading to specific molecular geometries like linear, trigonal planar, tetrahedral, etc.

Electron pair geometry considers the spatial arrangement of all electron pairs (bonding and lone pairs) around the central atom. Molecular geometry, however, describes the shape of the molecule based only on the positions of the atoms (ignoring lone pairs).