Question

Someone please distinguish the difference between hybrid atomic orbitals in valence bond theory and LCAO molecular orbitals in molecular orbital theory.

Answer 1

Ans- VALENCE BOND THEORY :
1) In valance bond theory,two atomic orbitals give an inter atomic orbital obtained by space filling of two unpaired electrons,one being in each of the two atomic orbitals
2) The resulting molecule,consist of atoms and retain their individual character
3) Atomic orbitals are mono-centric

4).Vb theory carries no concept of antibonding and bonding molecular orbital
5).It could not explain the para magnetic nature of oxygen
6).According to thos thoery no of bonds =no of unpaired electrons.
7) It can explain co-ordinate covalent bonds. .

MOLECULAR ORBITAL THEORY:
1) In molecular orbital theory,molecular orbitals are formed by linear combinations of atomic orbitals(LACO) method.
2) Atomic orbitals of the resulting molecule lose their individual identities.
3) Molecular orbitals are poly-centric.

4).MOT explains the bonding and antibonding molecular orbitals,
5).Accordin to this theory the no of bonds are
B.O= no electron present in bonding orbital -no of orbital in non bonding/2
6).It explains the paramagnet nature of o moleule
7).It also explainsthe formation of coordinate bondin