Question

what is main postulate of VESPR theory explain

Answer 1

Hey



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…

A lone pair of electrons occupies more space than bond pair

The electron pair are oriented around the central atom in such way , that the repulsion among them are minimum

The order of repulsion among various electron pairs will be in lp-lp>lp-bp>bp-bp

The magnitude of repulsion between bond pair's of electrons depend on the electro negativity difference between central atom and bonded atoms..

The repulsive forces exerted by various bonds on the adjacent bond pair are in the following order Triple bond>double bond>single bond

Please mark my answer as brainliesf if it was helpful to you

Answer 2

$\textbf{VESPER theory}$

[Valence Shell Electron Pair Repulsion Theory]

→ Lewis concept is unable to explain the shape of molecules. Then VESPER Theory explain the shapes of molecules. 

→ According to this theory, "The electron pair surroundimg the central atom repel one another. So, they moves away such that the repulsion between them and molecule has minimum energy and maximum stability.
_________________________________

$\huge\textbf{Postulates of VESPER theory}$

1) Shape of molecules depends upon the number of valence shell electron pairs around the central atom.

2) Valence shell electron pair repel each other so they take position such that they experience minimum repulsion.

3) Valence shell electrons which participate in bonding are called Bonding pair and which don't take part in bonding are called Non-bonding electron or lone pair.

* Their order of repulsion is LP - LP › LP - BP › BP - BP.

4) When molecule has only bond pair, then molecules has regular geometry.

5) When molecule or central atom has bond pair as well as lone pair, then it has irregular geometry.

→ Based on above postulates, molecules has various geometry and shape like linear, see-saw, T- shape, Tetrahedral, trigonal pyramidal, trigonal bipyramidal, octahedral, square planner, square bipyramidal. 
_________________________________

$\textbf{Limitations}$

→ Lewis and VESPER has many limitations to explain all the molecules shape. These limitations are explained by 2 Modern Theories, which are based upon quantum mechanics. 

→ These 2 Modern Theories are :-

* Valence bond theory.

* Molecular orbital theory.
_________________________________