Which of the following species is not paramagnetic?

Question

Aicharya · Accepted Answer

CO has no unpaired electron while other have unpaired electrons so, paramagnetic in nature.(Apply M.O.T)

Molecular orbital configuration \Rightarrow

CO : {like N}_{2}; σ 1 s^{2} < σ^{*} {1S}^{2} < σ 2 S^{2} < σ^{*} 2 S^{2} < π 2 P_{x}^{2} = π 2 P_{y}^{2} < σ 2 P_{z}^{2} (No unpaired electrons)

O_{2} : σ 1 S^{2} < σ^{*} {1S}^{2} < σ 2 S^{2} < σ^{*} 2 S^{2} < σ 2 P_{z}^{2} < π 2 P_{x}^{2} = π 2 P_{y}^{2} < π^{*} 2 P_{x}^{1} = π^{*} 2 P_{y}^{1} (2 unpaired electrons)

B_{2} : σ 1 S^{2} < σ^{*} 1 S^{2} < σ 2 S^{2} < σ^{*} 2 S^{2} < π 2 P_{x}^{1} = π 2 P_{y}^{1} (2 unpaired electrons)

NO : σ 1 S^{2} < σ^{*} 1 S^{2} < σ 2 S^{2} < σ^{*} 2 S^{2} < σ 2 P_{z}^{2} < π 2 P_{x}^{2} = π 2 P_{y}^{2} < π^{*} 2 P_{y}^{1} = π^{*} 2 P_{x}^{0} (1 unpaired electrons)

Solution