Stability of the species `Li_(2), Li_(2)^(-)` and `Li_(2)^(+)` increases in the order of

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

`Li_2` (3+3=6)=`sigma1s^2 sigma**1s^2 ,sigma2s^2`
Bond order = `(N_b-N_a)/2 =(4-2)/2=1`
`Li_2^+` (3+1-1=5) = `sigma1s^2 , sigma**1s^2 , sigma2s^2 , sigma**2s^1`
Bond order = `(3-2)/2=1/2=0.5`
`Li_2^(-) ` (3+3+1=7) = `sigma1s^2 , sigma**1s^2 , sigma2s^2 , sigma**2s^1`
Bond order =`(4-3)/2=1/2`=0.5