Stability of the species Li 2 ​ , Li 2 − ​ and Li 2 + ​ increases in the order:

Options

A. `Li_(2)lt Li_(2)^(+)lt Li_(2)^(-)`
B. `Li_(2)^(-)lt Li_(2)^(+)lt Li_(2)`
C. `Li_(2)lt Li_(2)^(-)lt Li_(2)^(+)`
D. `Li_(2)^(-)lt Li_(2)lt Li_(2)^(+)`

Answer

B

Explanation

Stability depends upon bond order :
`Li_(2) : KK (sigma_(2s))^(2)B.O = 1`
`Li_(2)^(+) : KK(sigma_(2s))^(1)B.O=0.5`
`Li_(2)^(-): KK (sigma_(2s))^(2)(sigma_(2s)^(**))^(1)B.O=0.5`
`Li_(2)^(+)` is more stable than `Li_(2)^(-)` because it has less number of antibonding electrons. Hence, `Li_(2)^(-)lt Li_(2)^(+)lt Li_(2)`.