*Question T5A07:
Why are metals generally good conductors of electricity?*  

*Correct Answer is  B: They have many free electrons*  

### AI Response: (may contain errors)  

Metals are generally good conductors of electricity primarily because they have many free electrons. Let's break down the correct answer and the other choices:

### Correct Answer: B - They have many free electrons
- **Explanation**: In metals, the atomic structure allows for some electrons to be loosely bound to their atoms. These free electrons can move easily throughout the metal when an electric field is applied, allowing for efficient conduction of electricity. This property is what makes metals excellent conductors.

### Why the Other Choices are Incorrect:
- **A: They have relatively high density**  
  - **Explanation**: While many metals do have high density, density alone does not determine electrical conductivity. Conductivity is more closely related to the availability of free electrons rather than the mass or density of the material.

- **C: They have many free protons**  
  - **Explanation**: Protons are positively charged particles found in the nucleus of an atom and do not move freely. Electrical conduction relies on the movement of charged particles, specifically electrons, not protons. Therefore, this statement is incorrect.

- **D: All these choices are correct**  
  - **Explanation**: Since choices A and C are incorrect, this option cannot be correct. Only choice B accurately describes why metals are good conductors.

### Summary
- Metals conduct electricity well due to the presence of many free electrons that can move easily.
- Density and free protons do not contribute to electrical conductivity in the same way.

This understanding is crucial for the Extra Class exam, as it highlights the fundamental properties of materials in relation to electrical conduction.