Which one of the following has the lowest melting point

Options

A. B
B. AI
C. Ga
D. TI

Answer

To determine which element among boron, aluminum, gallium, and thallium has the lowest melting point, we can analyze the properties of each element based on their atomic structure and bonding.

### Step-by-Step Solution:

1. **Understanding the Elements**:
- **Boron (B)**: A non-metal with a high melting point due to strong covalent bonding in its structure.
- **Aluminum (Al)**: A metal with a relatively high melting point, but lower than boron.
- **Gallium (Ga)**: A metal that has a unique property of melting at a low temperature (29.76 °C) due to weak metallic bonding.
- **Thallium (Tl)**: Another metal, but it has a higher melting point than gallium.

2. **Comparing Melting Points**:
- **Boron**: High melting point (around 2075 °C).
- **Aluminum**: Melting point of about 660 °C.
- **Gallium**: Melting point of approximately 29.76 °C.
- **Thallium**: Melting point around 304 °C.

3. **Identifying the Lowest Melting Point**:
- From the melting points listed, gallium has the lowest melting point compared to boron, aluminum, and thallium.

4. **Conclusion**:
- Therefore, the element with the lowest melting point among the given options is **Gallium (Ga)**.

### Final Answer:
Gallium has the lowest melting point among boron, aluminum, gallium, and thallium.

---