write about valence shell electron pair repulsion theory
Answers
ANSWER :
VALENCE SHELL ELECTRON PAIR REPULSION THEORY :
Sidgwick and Powell proposed this theory.
Gillespie and Nyholm improved it further to explain about the bond angles in a molecule.
According to this theory , shape of the molecule depends on number of valence shell electron pairs around the central atom.
The pair of electrons in the valence shell repel one another and the magnitude of repulsions is lone pair -lone pair >lone pair-bond pair>bond pair-bond pair.
Lone pairs occupy more space around the central atom than bond pairs.
The presence of lone pairs on the central atom causes slight distortion of bond angles from the expected regular shape.
The angle between lone pair and bond pair increases at the central atom due to more repulsions and the actual bond angle between atoms must be decreased.
VSEPR Theory mainly fails in explaininh the strengths of the bonds.
Answer:
Valence Shell Electron pair repulsion : -
(1) Sidgwick and Powell proposed valence shell electron pair repulsion theory to predict the shapes of covalent molecules
(2) It is based on idea that the electron pairs on the atoms in a molecule repel each other
(3) The atoms in a molecule arrange themselves in such a way that repulsion is minimised.
(1) The arrangement of electrons is called electron pair geometry