Definition of Vsepr Theory
VSEPR theory also known as valence shell electron pair repulsion theory dictates that the pairs of electrons present in the shell of an atom tend to repel each other whether they are in bond pair or in lone pair. The electrons have to maintain maximum distance from each other to minimize repulsion and to maximize attraction.
This theory emphasis not only the pair of electrons but also the groups of electrons (lone pair, unpaired electron, double bond, or triple bond). The shape of the molecules is predicted by the VSEPR theory. It is determined by the location of the nucleus and the electrons. According to VSEPR, water has tetrahedral geometry, carbon dioxide has liner geometry, etc.