Valence Bond Theory:-

According to this theory outermost orbitals of central atom become hybridized and converted to degenerate orbital. After its lone pair of legands make co-ordinate bond with Hybridised orbital to form a definate geometry.

C. No.	Hybridisation	Shape [Ag (NH3)2 ]
2	Sp	Linear
3	Sp2	Trigonal planer
4	Sp3 dsp2	Tetrahedral Square planer
5	Sp3d dsp3	Square pyramidal Trigonal bipyramidal
6	Sp3d2 d2sp3	Octahedral (outer) Octahedral (Inner)

 

Draw Back:-

This theory cannot describe stability. It cannot describe colours in complexes. In some complexes, i.e. jumps towards higher energy level.