Question

Explain that helium is monoatomic on the basis of molecular orbital theory

Answer 1

Based on molecular orbital theory, He 2 should not exist, and a chemical bond cannot form between the atoms. However, the v-a-n-d-e-r W-a-a-l-s force exists between helium atoms as shown by the existence of liquid helium, and at a certain range of distances between atoms the attraction exceeds the repulsion.