VSEPR theory uses electron pair repulsion to predict the geometry of molecules based on the number of electron pairs around the central atom. It postulates that the shape is determined by hybridization if there are only bond pairs, and the presence of lone pairs causes distortion from the ideal shape due to greater repulsion between lone pairs than between bond pairs. The type of hybridization and number of lone pairs also determines the bond angles. If all pairs are bond pairs and atoms are identical, changes in electronegativity do not affect the ideal molecular geometry.

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

6. • 2nd 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.

8. • 3rd 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.

9. 4th 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