To determine the number of paramagnetic species with a bond order of one, we analyze each given species:
Step 1: Identify Paramagnetic Species
Step 2: Calculate Bond Order
Bond order is calculated as: (Number of electrons in bonding orbitals-Number of electrons in antibonding orbitals)2
| Species | Electron Configuration | Paramagnetic? | Bond Order |
|---|---|---|---|
| H2 | (σ1s)² | No | 1 |
| He2+ | (σ1s)²(σ*1s)¹ | Yes | 0.5 |
| O2- | (σ2s)²(σ*2s)²(π2p)⁴(π*2p)³ | Yes | 1.5 |
| N2 | (σ2s)²(σ*2s)²(π2p)⁴(σ2p)² | No | 3 |
| O22- | (σ2s)²(σ*2s)²(π2p)⁴(π*2p)⁴ | No | 1 |
| F2 | (σ2s)²(σ*2s)²(π2p)⁴(π*2p)⁴(σ2p)² | No | 1 |
| Ne2+ | (σ2s)²(σ*2s)²(π2p)⁴(π*2p)⁴(σ2p)¹ | Yes | 0.5 |
| B2 | (σ2s)²(σ*2s)²(π2p)¹(π2p)¹ | Yes | 1 |
Final Results
The total number of species matching the criteria is: 1. This satisfies the range (1,1).
We analyze the magnetic behaviour and bond order for each species:
Among these, the only species that is both paramagnetic and has a bond order of 1 is: B2
Thus, the correct count is: 1.
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)

Cobalt chloride when dissolved in water forms pink colored complex $X$ which has octahedral geometry. This solution on treating with cone $HCl$ forms deep blue complex, $\underline{Y}$ which has a $\underline{Z}$ geometry $X, Y$ and $Z$, respectively, are
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)