Which of these are true regarding metallic bonds ?

Options

A. Luster of metals is due to oscillation of electrons on the surface of the metal
B. The best electric conductor is silver among all metals
C. Diamond is not a conductor of electricity and has a high value of energy gap
D. All of these are correct

Answer

To determine which statements are true regarding metallic bonds, let's analyze the properties of metallic bonds and the statements provided in the question.

### Step-by-Step Solution:

1. **Understanding Metallic Bonds**:
- Metallic bonds are characterized by a 'sea of electrons' that are free to move around, which allows metals to conduct electricity and heat. The positively charged metal ions are surrounded by these delocalized electrons.

2. **Analyzing the Statements**:
- **Statement 1**: Metals exhibit a shining surface due to the oscillation of electrons when light falls on them.
- **Explanation**: When light hits the surface of a metal, the electrons absorb energy and oscillate. As they return to their lower energy state, they emit light, giving metals their characteristic luster.
- **Conclusion**: This statement is true.

- **Statement 2**: Silver is the best electrical conductor among all metals.
- **Explanation**: Silver has a high number of free electrons due to its electronic configuration, which allows for easy movement of electrons, making it an excellent conductor of electricity.
- **Conclusion**: This statement is true.

- **Statement 3**: Diamond is a bad conductor of electricity due to its high energy gap.
- **Explanation**: Diamond has a tetrahedral structure where carbon atoms are tightly packed, resulting in no free electrons. The energy gap between the valence band and conduction band is significant, preventing electron flow.
- **Conclusion**: This statement is true.

3. **Final Conclusion**:
- Since all three statements regarding metallic bonds are true, the correct answer is that all options are correct.

### Answer:
The correct answer is option 4: All statements are true regarding metallic bonds.