Use the MO orbital order with pi_2p below sigma_2p for B2, C2 and N2, and sigma_2p below pi_2p for O2. Which species has bond order 2 and is diamagnetic?

JEE Advanced levelSingle correct optionDifficulty 3 of 3cb100

Use the MO orbital order with $π_{2 p}$ below $σ_{2 p}$ for $B X_{2}$ , $C X_{2}$ and $N X_{2}$ , and $σ_{2 p}$ below $π_{2 p}$ for $O X_{2}$ . Which species has bond order 2 and is diamagnetic?

C X_{2}

(8 valence electrons) has

σ_{2 s}^{2} σ_{2 s}^{* 2} π_{2 p}^{4}

: bond order

(6 - 2) /2 = 2

and all electrons paired.

O X_{2}

and

N X_{2} X^{2 -}

have bond order 2 but two unpaired electrons in

π^{*}

orbitals.

B X_{2}

has bond order 1 and two unpaired electrons.