Question: According to molecular theory, the species among the following that does not exist is:
$\mathrm{He}_{2}^{+}$
$\mathrm{He}_{2}^{-}$
$\mathrm{Be}_{2}$
$\mathrm{O}_{2}^{2-}$
Correct Option: , 3
Solution:
According to M.O.T. If bond order of chemical species is zero then that chemical species does not exist.
