Question

In the of the following pairs of molecules /ions both the species are not likely to exist?
A. `H_2^(2+), He_2`
B. `H_2^(+), He_2^(2-)`
C. `H_2^(-), He_2^(2+)`
D. `H_2^(-), He_2^(2-)`

Answer 1

Correct Answer - A
Species (molecules, ions) having zero or negative bond order do not exist. `He_2^(2+)` has no electron while `He_2` has 2 bonding electrons and 2 antibonding electrons. Thus, the bond order of `He_2^(2+)` and `He_2` is zero. Hence, their existence is not possible.