Question

What is Difference between VSEPR theory and Valence bond(VB) theory

Answer 1

VSEPR is a subset of valence bond. It's just a way of figuring out molecular geometries.The fundamental difference is that valence bond theory describes bonds as local structures, while molecular orbital treats them as more diffuse and spread out over the whole molecule.

In VB theory a bond is described by the two adjacent orbitals that go into making the bond. These orbitals are then populated relative to the atoms involved in the relevant bond(s).

Answer 2

VSEPR theory explaims the structure and geometrical shapes of different covalent bonds like bond betweenXeF6 , SO2, BF6 etc. It also involves calculating bond pairs and lone pairs using the formula 1/2 ×(v+m-c+a) .
While valence bond theory explains the metal atom under the influence of ligands uses its orbitals for hybridisation to give a set of equivalent orbitals of definite geometry. VBT OF tetrahedral and octahedral , square planar complexes.
VSEPR is in p block chapter
VBT is in coordination compound s chapter class 12