Question

Out of Mn\(^{2+}\) and Zn\(^{2+}\), which ion will be more paramagnetic and why? (Atomic numbers: Mn = 25, Zn = 30)

Hint:

More unpaired electrons → Greater paramagnetism.

Answer 1

Which ion will be more paramagnetic: Mn\(^{2+}\) or Zn\(^{2+}\)?
To determine which of the ions, Mn\(^{2+}\) or Zn\(^{2+}\), is more paramagnetic, we need to examine the number of unpaired electrons in each ion.

Step 1: Electron Configuration of Mn and Zn.
- Manganese (Mn) has an atomic number of 25. The electron configuration of Mn is:
\[ \text{Mn:} \, [Ar] 3d^5 4s^2 \]
When Mn forms a \( 2+ \) ion (Mn\(^{2+}\)), it loses two electrons, which are removed from the 4s orbital. The electron configuration of Mn\(^{2+}\) is:
\[ \text{Mn}^{2+}: \, [Ar] 3d^5 \]
So, Mn\(^{2+}\) has 5 electrons in its 3d orbitals, all of which are unpaired.

- Zinc (Zn) has an atomic number of 30. The electron configuration of Zn is:
\[ \text{Zn:} \, [Ar] 3d^{10} 4s^2 \]
When Zn forms a \( 2+ \) ion (Zn\(^{2+}\)), it loses two electrons from the 4s orbital. The electron configuration of Zn\(^{2+}\) is:
\[ \text{Zn}^{2+}: \, [Ar] 3d^{10} \]
Zn\(^{2+}\) has a completely filled 3d orbital with no unpaired electrons.

Step 2: Paramagnetism and Unpaired Electrons.
Paramagnetism occurs due to the presence of unpaired electrons. The more unpaired electrons an ion has, the stronger its paramagnetism.
- Mn\(^{2+}\) has 5 unpaired electrons in its 3d orbitals.
- Zn\(^{2+}\) has no unpaired electrons, as its 3d orbitals are completely filled.

Conclusion:
Mn\(^{2+}\) will be more paramagnetic than Zn\(^{2+}\) because Mn\(^{2+}\) has 5 unpaired electrons, while Zn\(^{2+}\) has no unpaired electrons. The presence of unpaired electrons in Mn\(^{2+}\) makes it more paramagnetic.