1. MOLECULAR ORBITAL THEORY

2. MOLECULAR ORBITAL THEORY
Molecular orbital (MO) theory was developed by
F. Hund and R.S. Mulliken in 1932

3. Linear combination of atomic orbital's (LCAO)
ψMO = ψA + ψB
σ and σ* are formed as :
σ = ψA + ψB ( Bonding MO)
σ* = ψA – ψB ( Anti bonding MO )

5. Conditions for the Combination of Atomic Orbitals
Same energy.
Same symmetry
Must overlap to the maximum extent

6. TYPES OF MO ORBITALS
σ (sigma),
π (pi),
δ (delta)

7. sigma (σ) molecular orbitals are symmetrical around the bond-axis
pi (π) molecular orbitals are not symmetrical

9. Energy of the MO Orbitals for O2 and F2
Energy of the MO Orbitals for Other molecules

10. MO ELECTRONIC CONFIGURATION FOR H2
Number of Electrons = 2

11. MO ELECTRONIC CONFIGURATION FOR He2
NUMBER OF ELECTRONS = 4
Bond order of He2 is ½(2 – 2) = 0

12. Lithium molecule Li2
No. of Electrons = 6

13. CARBON MOLECULE C2
No Of Electrons = 12

14. N MOLECULE

15. Oxygen molecule (O2 )

16. THANK YOU