According to MO theory which of thhe following lists makes the nitrogen species in terms of increasing bond order?

Options

A. `N_2^(-) lt N_2 lt N_2^(2-)`
B. `N_2^(2-) lt N_2^(-) lt N_2`
C. `N_2 lt N_2^(2-) lt N_2^(-)`
D. `N_2^(-) lt N_2^(2-) lt N_2`

Answer

B

Explanation

According to the molecular orbital theory (MOT),
`N_2`(7+7=14), =`sigma1s^2, overset***sigma1s^2, sigma2s^2, overset***sigma2s^2,pi2p_x^2~~2p_y^2,sigma2p_z^2`
Bond order `=(10-4)/2=3`
`N_2^-`(7+7+1=15), =`sigma1s^2, overset***sigma1s^2, sigma2s^2, overset***sigma2s^2,pi2p_z^2, 2p_x^2~~sigma2p_y^2,overset***pi2p_x^1`
Bond order `=(10-5)/2=2.5`
`N_2^(2-)`(7+7+2=16), =`sigma1s^2, overset***sigma1s^2, sigma2s^2, overset***sigma2s^2,pi2p_z^2, 2p_x^2~~sigma2p_y^2,overset***pi2p_x^1~~overset***pi2p_y^1`
Bond order `=(10-6)/2=2`
Hence, the increasing order of bond order is ,
`N_2^(2-) lt N_2^(-) lt N_2`