Number of paramagnetic oxides among the following is ____ {Li_2O,\ CaO,\ Na_2O_2,\ KO_2,\ MgO,\ K_2O}

🧠 Paramagnetic = has unpaired electrons. Check each oxide's structure.

| Compound | Anion present | Unpaired e? | |---|---|---| | $\ce{Li2O}$ | $\ce{O^{2-}}$ (oxide) — fully paired | ✗ | | CaO | $\ce{O^{2-}}$ — fully paired | ✗ | | $\ce{Na2O2}$ | $\ce{O2^{2-}}$ (peroxide) — BO=1, all paired | ✗ | | $\ce{KO2}$ | $\ce{O2-}$ (superoxide) — 1 unpaired in $\pi^*$ | ✓ | | MgO | $\ce{O^{2-}}$ — fully paired | ✗ | | $\ce{K2O}$ | $\ce{O^{2-}}$ — fully paired | ✗ |

Only $\ce{KO2}$ contains the superoxide ion ($\ce{O2-}$) which has 17 electrons and 1 unpaired electron.

$\boxed{\text{Answer: (a) 1}}$