`CuSO_4` is paramagnetic while `ZnSO_4` is diamagnetic because

Options

A. `Cu^(2+)` ion has `3d^9` configuration while `Zn^(2+)` ion has `3d^(10)` configuration
B. `Cu^(2+)` ion has `3d^5` configuration while `Zn^(2+)` ion has `3d^6` configuration
C. `Cu^(2+)` has half filled orbitals while `Zn^(2+)` has fully filled orbitals
D. `CuSO_4` is blue in colour while `ZnSO_4` is white.

Answer

To understand why CuSO₄ is paramagnetic while ZnSO₄ is diamagnetic, we need to analyze the electronic configurations of the copper and zinc ions involved in these compounds.

### Step-by-Step Solution:

1. **Define Paramagnetic and Diamagnetic:**
- **Paramagnetic Substances:** These substances have one or more unpaired electrons and are attracted to magnetic fields. They exhibit magnetic properties due to the presence of unpaired electrons.
- **Diamagnetic Substances:** These substances have all electrons paired and are weakly repelled by magnetic fields. They do not exhibit any magnetic properties due to the absence of unpaired electrons.

2. **Electronic Configuration of Copper (Cu):**
- The atomic number of copper (Cu) is 29. Its ground state electronic configuration is:
\[ \text{Cu: } [\text{Ar}] \, 3d^{10} \, 4s^1 \]
- When copper loses two electrons to form Cu²⁺, the electronic configuration becomes:
\[ \text{Cu}^{2+}: [\text{Ar}] \, 3d^9 \]
- In this configuration, there are 9 electrons in the 3d subshell, which means there is one unpaired electron.

3. **Electronic Configuration of Zinc (Zn):**
- The atomic number of zinc (Zn) is 30. Its ground state electronic configuration is:
\[ \text{Zn: } [\text{Ar}] \, 3d^{10} \, 4s^2 \]
- When zinc loses two electrons to form Zn²⁺, the electronic configuration becomes:
\[ \text{Zn}^{2+}: [\text{Ar}] \, 3d^{10} \]
- In this configuration, all 10 electrons in the 3d subshell are paired.

4. **Conclusion:**
- Since Cu²⁺ has an unpaired electron (3d⁹ configuration), CuSO₄ is paramagnetic.
- Zn²⁺ has all paired electrons (3d¹⁰ configuration), making ZnSO₄ diamagnetic.

### Final Answer:
CuSO₄ is paramagnetic because Cu²⁺ has an unpaired electron (3d⁹ configuration), while ZnSO₄ is diamagnetic because Zn²⁺ has all paired electrons (3d¹⁰ configuration).

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