Use molecular orbital theory to explain why the `Be_(2)` molecules do not exist?

Explanation

The atomic no. (Z) or Be is 4. This means that 8 electrons are to be filled in the M.O of `Be_(2).` The configuration is :
`[sigma_(1s)]^(2)"["overset(**)sigma_(1s)"]"^(2)[sigma_(2s)]^(2)"["overset(**)sigma_(2s)"]"^(2) , B.O = 1/2[N_(b)-N_(a)]=1/2[4-4]=0`
As the bond order comes out to be zero, the molecule of `Be_(2)` does not exist.