(A): `Cu^(+)` is diamagnetic
(R): Ions with `d^10` configuration are diamagnetic 

Options

A. Both A & R are true, R is the correct explanation of A
B. Both A & R are true, R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true

Answer

To solve the question, we need to analyze the statements (A) and (R) regarding the diamagnetism of the ion \( \text{Cu}^+ \) and the configuration of ions with \( d^{10} \).

### Step-by-Step Solution:

1. **Understand the Electronic Configuration of Copper**:
- The atomic number of copper (Cu) is 29. Its ground state electronic configuration is:
\[ \text{Cu}: [\text{Ar}] 3d^{10} 4s^1 \]

2. **Determine the Configuration of \( \text{Cu}^+ \)**:
- When copper loses one electron to form \( \text{Cu}^+ \), the electron is removed from the 4s orbital:
\[ \text{Cu}^+: [\text{Ar}] 3d^{10} \]
- This means \( \text{Cu}^+ \) has a \( d^{10} \) configuration.

3. **Check for Unpaired Electrons**:
- In the \( 3d^{10} \) configuration, all 10 electrons are paired. Therefore, there are no unpaired electrons in \( \text{Cu}^+ \).

4. **Determine Diamagnetism**:
- A species is considered diamagnetic if it has no unpaired electrons. Since \( \text{Cu}^+ \) has no unpaired electrons, it is indeed diamagnetic.

5. **Analyze Statement (R)**:
- The statement (R) claims that ions with a \( d^{10} \) configuration are diamagnetic. This is true because any ion with a fully filled d-subshell (10 electrons) will have all electrons paired, leading to diamagnetism.

6. **Conclusion**:
- Since both statements (A) and (R) are true, and (R) correctly explains (A), we conclude that:
- Both A and R are true, and R is the correct explanation of A.

### Final Answer:
The correct option is: **Both A and R are true, and R is the correct explanation of A.**

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