Use molecular orbital theory to explain why Be, molecule does not exist.

Explanation

The atomic no.(z) of Be is 4. This means that S electrons are to be filled in the M.O. of `Be_2`. The configuration is: ` sigma 1s^2 sigma ^* 1s^2 sigma 2s^2 sigma^* 2s^2 `
`B.O = 1/2 [N_b-N_a]=1/2 [4-4] =0`
As bond order of `Be_2` is zero, the molecule of `Be_2` does not exit.