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, we can analyze the properties of metals and the nature of metallic bonding. Here’s a step-by-step breakdown:

### Step 1: Understanding Metallic Bonds
Metallic bonds are formed due to the electrostatic attraction between positively charged metal ions and a sea of delocalized electrons. This unique structure gives metals their characteristic properties.

### Step 2: Analyzing the Options
1. **Luster of Metals**: The luster of metals is indeed due to the oscillation of delocalized electrons on the surface of the metal. When light hits the surface, these electrons can absorb and re-emit light, giving metals their shiny appearance.

2. **Electrical Conductivity**: While silver is one of the best conductors of electricity among metals, it is important to note that copper is often used in electrical wiring due to its excellent conductivity and lower cost. Therefore, the statement regarding silver being the best conductor is somewhat misleading but not entirely wrong.

3. **Diamond as a Conductor**: Diamond is a form of carbon with a very strong covalent bond structure and does not have free electrons, making it an insulator. Therefore, the statement about diamond not being a conductor is true.

### Step 3: Conclusion
Based on the analysis:
- **True Statement**: The luster of metals is due to the oscillation of electrons on the surface.
- **Misleading Statement**: While silver is a great conductor, the statement could be interpreted as implying it is the absolute best without considering other factors.
- **True Statement**: Diamond is not a conductor of electricity.

### Final Answer
The correct option regarding metallic bonds is:
- **Option A**: The luster of the metal is due to the oscillation of electrons on the surface of the metal.