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explain the formation of H2 molecule with the help of V.B theory

Formation of Hydrogen(H2) molecule:

Hydrogen has one electron which is present in its 1s orbital. Suppose we have two hydrogen atoms HA and HB with their corresponding electrons eA and eB respectively. When the two hydrogen atoms are present at large distance from each other, there is practically no interaction between the two atoms.  When the two atoms come closer, they begin to interact with each other. As  a result, the following new forces of attraction and repulsion come into operation. 

The attractive forces tend to bring the two atoms closer whereas repulsive forces  tend to push them apart. The magnitude of attractive forces is greater than the repulsive forces. Therefore, the atoms go on approaching each other and the potential energy of the system continuously decreases. Ultimately, a point is reached where forces of attraction exactly cancels the repulsive forces. This point is reached when the atoms are held  up at critical distance Re.  At a distance greater than Re, the forces of attraction dominate whereas at a distance less than Re the repulsive forces are dominant.  Energy is minimum at critical distance Re. This critical distance is called bond length or inter nuclear distance.


                -----------------------Re--------------------------------------------->R


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