The electropositive character is the maximum for which of the following elements in Group 13?

Options

A. AI
B. T1
C. B
D. In

Answer

To determine which element in Group 13 has the maximum electropositive character, we can follow these steps:

### Step 1: Identify the Elements in Group 13
Group 13 elements include boron (B), aluminium (Al), gallium (Ga), indium (In), and thallium (Tl). However, the question specifies boron, aluminium, indium, and thallium.

### Step 2: Understand Electropositive Character
Electropositive character refers to the ability of an element to donate electrons. The more readily an element can donate electrons, the more electropositive it is.

### Step 3: Analyze the Trend in Group 13
As we move down the group from boron to thallium, we observe the following trends:
- The atomic size increases due to the addition of electron shells.
- Larger atomic size generally leads to a greater ability to lose electrons, thus increasing electropositivity.

### Step 4: Compare Boron and Aluminium
- Boron is smaller in size compared to aluminium, which makes it harder for boron to lose electrons.
- Aluminium, being larger, has a higher tendency to donate electrons compared to boron.

### Step 5: Compare Aluminium, Indium, and Thallium
- As we move from aluminium to indium and thallium, we must consider the effect of d and f orbitals.
- The presence of d and f orbitals introduces a screening effect, which reduces the effective nuclear charge felt by the outermost electrons.
- This results in a decreased tendency to lose electrons as we move from aluminium to thallium.

### Step 6: Conclusion
Based on the analysis, aluminium is the most electropositive element among boron, aluminium, indium, and thallium. Therefore, the answer is aluminium.

### Final Answer:
Aluminium (Al) has the maximum electropositive character in Group 13.

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