Valence Bond Theory
Basically, any covalent bond comes about because of the cover of nuclear orbital’s. This thought shapes the reason for a quantum mechanical hypothesis called valence bond (VB) hypothesis. In valence bond theory, the electrons in a molecule are assumed to occupy atomic orbital’s of the individual atoms and a bond results from overlap of those orbital’s.
Electrons occupy atomic orbital’s.
Covalent bonds result from the cover of nuclear orbital’s.