VSEPR theory, or Valence Shell Electron Pair Repulsion theory, is a model used in chemistry to predict the shape of molecules. It is based on the idea that electron pairs surrounding a central atom will arrange themselves as far apart as possible to minimize repulsion. This arrangement helps determine the three-dimensional structure of the molecule, which is crucial for understanding its chemical properties and reactivity. The shapes predicted by VSEPR theory include linear, trigonal planar, tetrahedral, and octahedral, among others. Each shape corresponds to a specific number of bonding and non-bonding electron pairs around the central atom. By analyzing these arrangements, chemists can better understand how molecules interact with one another.