Number of molecules having bond order 2 from the following molecule is \_\_\_\_ . $\mathrm{C}_{2}, \mathrm{O}_{2}, \mathrm{Be}_{2}, \mathrm{Li}_{2}, \mathrm{Ne}_{2}, \mathrm{~N}_{2}, \mathrm{He}_{2}$

JEE Main · 2024 · 08 Apr 2024 · Shift 2 · Chemical Bonding and Molecular Structure

Number of molecules having bond order 2 from the following molecule is ____ .

C_{2}, O_{2}, Be_{2}, Li_{2}, Ne_{2}, N_{2}, He_{2}

Answer: 2

Bond order

= (N_{b} - N_{a}) /2

from MO configuration.

C_{2}

(12e

^{-}

σ 1 s^{2} σ^{*} 1 s^{2} σ 2 s^{2} σ^{*} 2 s^{2} π 2 p_{x}^{2} π 2 p_{y}^{2}

, BO

= (8 - 4) /2 = 2

O_{2}

(16e

^{-}

): BO

= (10 - 6) /2 = 2

B e_{2}

(8e

^{-}

): BO

= (4 - 4) /2 = 0

L i_{2}

(6e

^{-}

): BO

= (4 - 2) /2 = 1

N e_{2}

(20e

^{-}

): BO

= 0

N_{2}

(14e

^{-}

): BO

= 3

H e_{2}

(4e

^{-}

): BO

= 0

.
Molecules with bond order 2:

C_{2}

and

O_{2}

— count

= 2

JEE Main · 2024 · 08 Apr 2024 · Shift 2 · Integer answer