The number of species from the following which are paramagnetic and with bond order equal to one is \_\_\_\_. $\mathrm{H}_{2}, \mathrm{He}_{2}^{+}, \mathrm{O}_{2}^{+}, \mathrm{N}_{2}^{2-}, \mathrm{O}_{2}^{2-}, \mathrm{F}_{2}, \mathrm{Ne}_{2}^{+}, \mathrm{B}_{2}$

JEE Main · 2024 · 29 Jan 2024 · Shift 1 · Chemical Bonding and Molecular Structure

The number of species from the following which are paramagnetic and with bond order equal to one is ____.

H_{2}, He_{2}^{+}, O_{2}^{+}, N_{2}^{2 -}, O_{2}^{2 -}, F_{2}, Ne_{2}^{+}, B_{2}

Answer: 1

Molecular-orbital bond orders and magnetic behaviour:

H_{2}

: BO=1, diamagnetic.

He_{2}^{+}

: BO=0.5, paramagnetic.

O_{2}^{+}

: BO=2.5, paramagnetic.

N_{2}^{2 -}

: BO=2, paramagnetic.

O_{2}^{2 -}

: BO=1, diamagnetic.

F_{2}

: BO=1, diamagnetic.

Ne_{2}^{+}

: BO=0.5, paramagnetic.

B_{2}

: BO=1, paramagnetic.

Only

B_{2}

is both paramagnetic and has bond order exactly 1.

Key confirmed: 1.

JEE Main · 2024 · 29 Jan 2024 · Shift 1 · Integer answer