Question

Helium molecule does not exist why

Answer 1

The helium dimer is a van der Waals moleculewith formula He2 consisting of two heliumatoms.[2] This chemical is the largest diatomic molecule—a molecule consisting of two atoms bonded together. The bond that holds this dimer together is so weak that it will break if the molecule rotates, or vibrates too much. It can only exist at very low cryogenictemperatures.Two excited helium atoms can also bond to each other in a form called an excimer. This was discovered from a spectrum of helium that contained bands first seen in 1912. Written as He2* with the * meaning an excited state, it is the first known Rydberg molecule.[3]

Several dihelium ions also exist, having net charges of negative one, positive one, and positive two. Two helium atoms can be confined together without bonding in the cage of a fullerene.

Answer 2

The reasons why helium molecule does not exist are :

• The atomic number of helium is two. The two electrons fill the first orbital shell ( 1s).
• When two helium atoms come closer, the force of repulsion is more than the force of attraction, which decreases the stability.
• The bond order of the helium molecule is zero following the molecular orbital theory.
• So, no bond can exist between two helium atoms and the helium molecule does not exist.