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

Answer

D

Explanation

`H_(2)^(2+):(sigma1s)^(0)`
Bond order = 0
`He_(2):(sigma1s)^(2)(sigma^(**)1s)^(2)`
Bond order `(2-2)/(2)=0`
Hence, `He_(2)^(2+)` and `He_(2)` have zero bond order.