postulates of VSEPR theory

ITS ALL ABOUT THE STRUCTURE AND BONDING OF MOLECULE.

1. VSEPR THEORY

2. INTRODUCTION Valence shell electron pair repulsion theory. It is given by Gllispe and Nhyhom . It is the space model that is obtain after joining the points represent bonded atoms. That means lone pair are not consider in the shape of the molecule In order to represent the shape of the molecule atleast three atom and two bonded pair are required.

3. Valence shell electron pair repulsion ( VSEPR ) theory is a model used to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms.

4. POSTULATES OF VSEPR THEORY If all electron pair around the central atom are bond pair and there are no lone pair then shape of the molecule depends upon nature of hybridisation. N =no. Of valence electron in central atom + no. Of univalent atom +- charge / 2

5. 2 nd postulate – If all electron pair around the central atom are not bond pair , thier are some lone pair also then molecule posses a distorted shape because of lone pair –lone pair repulsion, bond pair –bond pair repulsion and thier relative order is . l.p.-l.p . > l.p.-b.p . > b.p – b.p .

6. 3 rd postualtes :- It deals with the bond angle of the molecule. Identify the type of hybridisation , % s character increases, bond angles increases. if no.of lone pair , no. Of lone pair increases then bond angle increases.

7. 4 th postulates If all electron pair around the central atom are bond pair and all surrounding atoms are identical then change of electronegativity in central atom as well as in the surrounding atom . So posses ideal shape