In which of the following pairs of molecules/ions, both the species are not likely to exist?

Options

A. `H_(2)^(+), He_(2)^(2-)`
B. `H_(2)^(-), He_(2)^(2-)`
C. `H_(2)^(2+), He_(2)`
D. `H_(2)^(-), He_(2)^(2+)`

Answer

C

Explanation

Species having zero or negative bond order do not exist.
`H_(2)^(2+)(1+1-2=0)=sigma1s^(0)" "` Bond order `=0`
`He_(2)(2+2=4)=sigma1s^(2), overset(***)sigma1s^(2)" "` Bond order `=(N_(b)-N_(a))/(2)=(2-2)/(2)=0" "` So, both `H_(2)^(2+) and He_(2)` do not exist.