Group 13 elements show +1 and +3 oxidation states. Relative statibility of +3 oxidation may be given as

Options

A. `TI^(+) gt In^(3+) gt Ga^(3+) gt AI^(3+) gt B^(3+)`
B. `B^(3+) gt AI^(3+) gt Ga^(3+) gt In^(3+) gt TI^(3+)`
C. `AI^(3+) gt Ga^(3+) gt TI^(3+) gt In^(3+) gt B^(3+)`
D. `AI^(3+) gt B^(3+) gt Ga^(3+) gt TI^(3+) gt In^(3+)`

Explanation

To determine the relative stability of the +3 oxidation state of Group 13 elements (Boron family), we can analyze the trend in oxidation states as we move down the group. Here’s a step-by-step solution:

### Step 1: Identify Group 13 Elements
The Group 13 elements include Boron (B), Aluminum (Al), Gallium (Ga), Indium (In), and Thallium (Tl).

### Step 2: Understand Oxidation States
Group 13 elements can exhibit +1 and +3 oxidation states. The +3 oxidation state is due to the loss of three electrons from the outermost shell.

### Step 3: Analyze the Inert Pair Effect
As we move down the group from Boron to Thallium, the inert pair effect becomes significant. The inert pair effect refers to the tendency of the two electrons in the outermost s-orbital (ns²) to remain non-bonding and not participate in bonding.

### Step 4: Explain the Inert Pair Effect Mechanism
The inert pair effect arises due to the poor shielding of the d and f orbitals. As we go down the group, the d and f orbitals increase in number and size, leading to weak shielding of the nuclear charge. This results in a stronger attraction of the nucleus towards the outermost electrons.

### Step 5: Evaluate the Stability of +3 Oxidation State
- **Boron (+3)**: Highly stable due to its small size and effective nuclear charge.
- **Aluminum (+3)**: Less stable than Boron but still relatively stable.
- **Gallium (+3)**: Even less stable than Aluminum due to the inert pair effect.
- **Indium (+3)**: Further decrease in stability compared to Gallium.
- **Thallium (+3)**: Very unstable; Thallium prefers to show +1 oxidation state due to the inert pair effect.

### Step 6: Summarize the Relative Stability
The stability of the +3 oxidation state decreases as we move down the group:
- **Boron** > **Aluminum** > **Gallium** > **Indium** > **Thallium**

Thus, the relative stability of the +3 oxidation state can be summarized as follows:
- Boron (+3) is the most stable.
- Thallium (+3) is the least stable and often does not exhibit this oxidation state.

### Final Answer:
The relative stability of the +3 oxidation state in Group 13 elements decreases from Boron to Thallium.

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