Chemistry > Chemical Bonding and Molecular Structure > 13.0 Molecular Orbital Theory
Chemical Bonding and Molecular Structure
1.0 Ionic Bond or Electrovalent Bond
2.0 Lattice Energy
3.0 Characteristics of Electrovalent Compounds
4.0 Covalent Bond (By Mutual Sharing of Electrons)
5.0 Characteristics of Covalent Compounds
6.0 Fajan’s Rule
7.0 Hydrogen Bonding
8.0 Coordinate Bond
9.0 Valence Shell Electron Pair Repulsion (VSEPR) Theory
10.0 Valence Bond Theory
11.0 Sigma and Pi Bonds ($\sigma $ and $\pi $ Bonds)
12.0 Hybridisation
12.1 Types of hybridization and spatial orientation of hybrid orbitals
12.2 Method of predicting the Hybrid state of the central atom in covalent molecules of polyatomic ions
13.0 Molecular Orbital Theory
13.1 Bond order
12.2 Method of predicting the Hybrid state of the central atom in covalent molecules of polyatomic ions
It may be defined as the half the difference between the number of electrons present in the bonding orbitals and the anti-bonding orbitals i.e.,
$$Bond\;order(B.O.) = \frac{{{\text{No}}{\text{. of electrons in }}BMO - {\text{No}}{\text{. of electrons in }}ABMO}}{2}$$
A positive bonding order suggest a stable molecule while a negative bond order or zero bond order suggest an unstable molecule.
Magnetic Behaviour:
If all the molecular orbitals in species are spin paired, the substance is diamagnetic. However, if one or more molecular orbitals are singly occupied it is paramagnetic.
