Question

Amongst the following the number of oxide(s) which are paramagnetic in nature is Na$_2$O, KO$_2$, NO$_2$, N$_2$O, ClO$_2$, NO, SO$_2$, Cl$_2$O

• A. 2
• B. 3
• C. 4
• D. 5

Answer 1

Answer: (C)

4

Answer 2

Paramagnetism arises from unpaired electrons. We analyze each species:

• Na$_2$O: Diamagnetic (all electrons paired in O$^{2-}$).
• KO$_2$: Paramagnetic (O$_2^-$ ion has 13 valence electrons, with one unpaired electron).
• NO$_2$: Paramagnetic (17 valence electrons, odd number means unpaired electrons).
• N$_2$O: Diamagnetic (16 valence electrons, all paired in Lewis structure).
• ClO$_2$: Paramagnetic (19 valence electrons, odd number means unpaired electrons).
• NO: Paramagnetic (11 valence electrons, odd number means unpaired electrons).
• SO$_2$: Diamagnetic (18 valence electrons, all paired).
• Cl$_2$O: Diamagnetic (20 valence electrons, all paired).

The paramagnetic oxides are KO$_2$, NO$_2$, ClO$_2$, and NO. There are 4 such oxides.