Valence Bond Theory

This theory was put forwarded by Hitler and London in 1931 A.D. This theory is based on the orbital picture of wave mechanics.

Assumption of Valance bond theory:

  1. A covalent bond is formed by the overlapping of half filled orbital of one atom with the half filled orbital of another atom.
  2.  The half filled orbital should have their electron with opposite spin.
  3. During the overlapping of atomic orbital, pairing of the electrons takes place and there is also decrease in the energy of the bonded atom.
  4. The greater is the extent of overlapping, the stronger is the covalent bond formation.
  5.  Depending upon the nature of atomic orbital involved and the extent of overlapping, the covalent bond can be divided into two types: Sigma bond and pi bond.

Limitation of valence bond theory:

  • This theory does not take into account the effect of non-bonding electrons on the overlap between the two orbitals.
  • This theory does not explain the diamagnetic and paramagnetic properties of a compound.

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One Response to “Valence Bond Theory”

  1. saddam chauhan

    notes are very helpful..