Question

What is the main principle of VSEPR theory?? What are it's postulates for ?? Please explain.

Thank you

Answer 1

The basic principle of the VSEPR theory is that molecular geometry can be predicted based on the notion that electron pairs in molecules tend to repel each other and achieve a maximum separation from each other. This applies both to bonding electrons as well as lone pairs.

This theory was proposed by sidgwick later it was developed by Gillespie and nyholm..

Postulates…

1. the shape of the molecule is determined by the repulsion between all of the electron pairs I.e lone and bond pair present in the atom…
2. A lone pair of electrons occupies more space than bond pair
3. The electron pair are oriented around the central atom in such way , that the repulsion among them are minimum
4. The order of repulsion among various electron pairs will be in lp-lp>lp-bp>bp-bp
5. The magnitude of repulsion between bond pair's of electrons depend on the electro negativity difference between central atom and bonded atoms..
6. The repulsive forces exerted by various bonds on the adjacent bond pair are in the following order Triple bond>double bond>single bond

for explanation click here and you can also check here