Question: According to molecular orbital theory, the species among the following that does not exist is:
$\mathrm{He}_{2}^{-}$
$\mathrm{He}_{22}^{+}$
$\mathrm{O}_{2}^{2-}$
$\mathrm{Be}_{2}$
Correct Option: , 4
Solution:
B. O. of $B e_{2}$ is zero, So it does not exist.
