Question

Out of KMnO4 and K2MnO4, which one is paramagnetic and why?

Hint:

Paramagnetic substances have unpaired electrons, while diamagnetic substances have all electrons paired.

Answer 1

To ascertain which compound is paramagnetic, we must analyze the oxidation state and the electron configuration of the manganese ion within each compound. - KMnO$_4$ (Potassium permanganate): The manganese ion in KMnO$_4$ is in the \(+7\) oxidation state (Mn$^{7+}$). Its electron configuration is \( 3d^0 4s^0 \), indicating empty d-orbitals. Lacking unpaired electrons, KMnO$_4$ is diamagnetic.
- K$_2$MnO$_4$ (Potassium manganate): In K$_2$MnO$_4$, the manganese ion is in the \(+6\) oxidation state (Mn$^{6+}$). The electron configuration of Mn$^{6+}$ is \( 3d^1 4s^0 \), showing one unpaired electron in the d-orbital. The presence of at least one unpaired electron makes K$_2$MnO$_4$ paramagnetic.


Step 1: Determine the oxidation state of manganese in each compound.


Step 2: Verify the count of unpaired electrons in the electron configuration of the manganese ion.