The metallic lustre of sodium is explanined by the presence of

Options

A. `Na^(o+)` ions
B. The oscillation of loosely bound electrons
C. Loosely held electectrons
D. bacc lattice

Answer

To solve the question regarding the metallic luster of sodium, we will analyze the options provided and explain the phenomenon step by step.

### Step-by-Step Solution:

1. **Understanding Metallic Luster**:
- Metallic luster refers to the shiny appearance of metals. It is a characteristic feature of metals, including sodium.

2. **Role of Electrons**:
- The luster is primarily due to the behavior of electrons in the metal. In metals, particularly alkali metals like sodium, there are free or loosely bound electrons that can move easily.

3. **Interaction with Light**:
- When light strikes the surface of sodium, these free electrons absorb energy from the light. This causes them to oscillate or vibrate around their mean position.

4. **Excitation of Electrons**:
- As the electrons absorb energy, they get excited to higher energy levels. This means they move from their original position to a higher energy state.

5. **Emission of Light**:
- After the electrons are excited, they eventually return to their original lower energy state. When they do this, they release the absorbed energy in the form of light.

6. **Resulting Luster**:
- The emitted light is what gives sodium its characteristic metallic luster. The oscillation of these loosely bound electrons is crucial for this process.

7. **Conclusion**:
- Therefore, the metallic luster of sodium is explained by the presence of loosely bound electrons that can oscillate and emit light when they return to their lower energy state.

### Answer:
The metallic luster of sodium is explained by the presence of loosely bound electrons (Option B).

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