Which of the following does not show electrical conductance?

Options

A. Potassium
B. Graphite
C. Dimond
D. Sodium

Explanation

To determine which of the given options does not show electrical conductance, we will analyze each option based on their properties.

### Step-by-Step Solution:

1. **Identify the options**: The options provided are:
- Potassium
- Graphite
- Diamond
- Sodium

2. **Analyze Potassium**:
- Potassium is a metal. Metals are known for their ability to conduct electricity due to the presence of free-moving electrons.
- **Conclusion**: Potassium shows electrical conductance.

3. **Analyze Graphite**:
- Graphite has a layered structure where each carbon atom is bonded to three others in a plane, leaving one electron free to move. This delocalization of electrons allows graphite to conduct electricity.
- **Conclusion**: Graphite shows electrical conductance.

4. **Analyze Diamond**:
- Diamond is also made of carbon, but it has a tetrahedral structure where each carbon atom is bonded to four other carbon atoms. This structure does not allow for free-moving electrons, as all electrons are localized in covalent bonds.
- **Conclusion**: Diamond does not show electrical conductance.

5. **Analyze Sodium**:
- Sodium, like potassium, is a metal and has free-moving electrons that allow it to conduct electricity.
- **Conclusion**: Sodium shows electrical conductance.

6. **Final Conclusion**:
- Among the options, diamond is the only substance that does not show electrical conductance.

### Answer:
**Diamond does not show electrical conductance.**

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