Question

Number of paramagnetic oxides among the following given oxides is __
$L{i}_{2}O,CaO,N{a}_2{O}_2,K{O}_2,MgO$ and $K_{2}O$

• A. 1
• B. 2
• C. 3
• D. 0

Answer 1

Answer: (A)

$L{i}_{2}O\Rightarrow 2L{i}^{+}{O}^{2-}$
$CaO\Rightarrow C{a}^{2+}{O}^{2-}$
$N{a}_2{O}_2\Rightarrow 2N{a}^{+}{O}_2^{2-}$
$K{O}_2\Rightarrow K^{+}{O}_2^{-}$
$MgO\Rightarrow M{g}^{2+}{O}^{2-}$
$K_{2}O\Rightarrow 2K^{+}{O}^{2-}$
$O_2^{-}\Rightarrow$ Complete octet, diamagnetic
$O^{2-}\Rightarrow {\sigma }_{1s}^2{\sigma }_{1s}^{\ast 2}{\sigma }_{2s}^2{\sigma }_{2s}^{\ast 2}{\sigma }_{2px}^2{\pi }_{2py}^2\simeq {\pi }_{2pz}^2{\pi }_{2py}^{\ast 2}\simeq {\pi }_{2pz}^{\ast 2}$ (dia)
$O_2^{-}\Rightarrow {\sigma }_{1s}^2{\sigma }_{1s}^{\ast 2}{\sigma }_{2s}^2{\sigma }_{2s}^{\ast 2}{\sigma }_{2px}^2{\pi }_{2py}^2\simeq {\pi }_{2pz}^2{\pi }_{2py}^{\ast 2}\simeq {\pi }_{2pz}^{\ast 1}$ (para)