In the 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 does not exist.
`B_(2)^(2+) (1+1-2=0) = sigma 1s^(0)`
Bond order `=0`
`He_(2) (2+2=4) = sigma 1s^(2), sigma_(1s^(2)`
Bond order `= (N_(b)-N_(a))/(2) = (2-2)/(2) = 0`
So, both `H_(2)^(2+)` do not exist.