Question

Using molecular orbital theory explain why BE2 MOLECULES does not exist.

Question of class 11
Plzz help.....

Answer 1

When , we draw the flow chart of bonding and anti-bonding orbitals of Beryllium two atoms, then both the bonding and anti-bonding orbitals come out to be completely filled.
And , thus the bond order formula becomes invalid since
Bond order = 1/2 ( Filled Bonding molecular orbitals - Filled Anti-bonding molecular orbitals) = 1/2(2-2) = 0
Thus, since the bond order comes out to be zero and this we can practically say that Be2 cannot exist.