The elements having the maximum and minimum melting points among the members of group 13 are respectively

Options

A. B, TI
B. TI,B
C. B, Ga
D. Al,TI

Answer

To determine the elements with the maximum and minimum melting points among the members of Group 13, we will analyze the elements in this group step by step.

### Step 1: Identify the Elements in Group 13
Group 13 of the periodic table is known as the boron family. The elements in this group are:
- Boron (B)
- Aluminium (Al)
- Gallium (Ga)
- Indium (In)
- Thallium (Tl)

### Step 2: Understand the General Trend of Melting Points
In most groups of the periodic table, the melting point tends to decrease as you move down the group. However, Group 13 exhibits some irregularities in this trend.

### Step 3: Analyze the Melting Points of Each Element
- **Boron (B)**: Has a high melting point due to its small size and strong covalent bonding. The melting point of boron is approximately 2075 °C.
- **Aluminium (Al)**: Has a melting point of about 660 °C.
- **Gallium (Ga)**: Has a melting point of about 29.76 °C, which is very low and close to room temperature. In fact, gallium can exist as a liquid at room temperature.
- **Indium (In)**: Has a melting point of approximately 1566 °C.
- **Thallium (Tl)**: Has a melting point of about 304 °C.

### Step 4: Determine Maximum and Minimum Melting Points
From the melting points analyzed:
- **Maximum Melting Point**: Boron (2075 °C)
- **Minimum Melting Point**: Gallium (29.76 °C)

### Conclusion
Thus, the elements having the maximum and minimum melting points among the members of Group 13 are respectively:
- **Maximum**: Boron (B)
- **Minimum**: Gallium (Ga)

### Final Answer
**Boron (B) has the maximum melting point, and Gallium (Ga) has the minimum melting point.**

---