Which is a diamagnetic material?

Options

A. Ni
B. Na
C. Au
D. Pt

Answer

To determine which material is a diamagnetic substance from the given options, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definitions**:
- **Diamagnetic Materials**: These materials are characterized by having all their electrons paired. They are weakly repelled by a magnetic field.
- **Paramagnetic Materials**: These materials have unpaired electrons and are attracted to a magnetic field.
- **Ferromagnetic Materials**: These materials exhibit permanent magnetism and have a strong attraction to magnetic fields.

2. **Analyze the Given Options**:
- **A. Nickel (Ni)**: This is a ferromagnetic material.
- **B. Sodium (Na)**: This is a paramagnetic material.
- **C. Gold (Au)**: This is a diamagnetic material.
- **D. Platinum (Pt)**: This is a paramagnetic material.

3. **Identify the Diamagnetic Material**:
- From the analysis, the only material that is classified as diamagnetic among the options is **Gold (Au)**.

4. **Conclusion**:
- Therefore, the answer to the question "Which is a diamagnetic material?" is **Gold (Au)**.