Solids having highest energy level partially filled with electrons are

Options

A. swmiconductor
B. conductor
C. insulator
D. none of these

Explanation

To solve the question, "Solids having highest energy level partially filled with electrons are," we need to understand the concepts of energy bands in solids, particularly focusing on the conduction band and how it relates to different types of materials.

### Step-by-Step Solution:

1. **Understanding Energy Bands**:
- In solids, electrons occupy energy levels that are grouped into bands. The two most important bands are the valence band and the conduction band.

2. **Defining the Conduction Band**:
- The conduction band is the highest energy band that is partially filled with electrons. This means that there are available energy states for electrons to move into, which allows for electrical conduction.

3. **Types of Materials Based on Band Filling**:
- **Conductors**: In conductors (like metals), the conduction band is either partially filled or overlaps with the valence band, allowing electrons to flow freely and conduct electricity.
- **Semiconductors**: In semiconductors, the conduction band is typically empty at absolute zero but can be partially filled at higher temperatures or when doped with impurities, allowing for some conduction.
- **Insulators**: In insulators, the conduction band is completely empty, and there is a significant energy gap between the valence band and the conduction band, preventing conduction.

4. **Conclusion**:
- Therefore, solids that have their highest energy level (the conduction band) partially filled with electrons are classified as **conductors** and **semiconductors**.

### Final Answer:
Solids having the highest energy level partially filled with electrons are **conductors** and **semiconductors**.