In order to represent the shape of the molecule atleast three atom and two bonded pair are required.Valence shell electron pair repulsion (VSEPR)theoryis a model used to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms.In order to represent the shape of the molecule atleast three atom and two bonded pair are required. Valence shell electron pair repulsion (VSEPR)theoryis a model used to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms.The main postulates of VSEPR theory are(1) For polyatomic molecules containing 3 or more atoms, one of the atoms is called the central atom to which other atoms are linked.(2) The geometry of a molecule depends upon the total number of valence shell electron pairs (bonded or not bonded) present around the central atom and their repulsion due to relative sizes and shapes.(3) If the central atom is surrounded by bond pairs only. It gives the symmetrical shape to the molecule.(4) If the central atom is surrounded by lone pairs (lp) as well as bond pairs (bp) of then the molecule has a distorted geometry.(5) The relative order of repulsion between electron pairs is as follows: lp – lp > lp – bp > bp – bp.