STATEMENT-1 : Out of all actinoids , Th has highest melting point .
and
STATEMENT-2: Th has largest size among actinoids .

Options

A. Statement-1 is True , Statement-2 is True , Statement-2 is a correct explanation for Statement-1
B. Statement-1 is True , Statement-2 is True , Statement-2 is NOT a correct explanation for Statement-1
C. Statement-1 is True , Statement-2 is False
D. Statement-1 is False , Statement-2 is True

Answer

To analyze the given statements regarding thorium (Th) and the actinoids, we will evaluate each statement step by step.

### Step 1: Evaluate Statement 1
**Statement 1:** "Out of all actinoids, Th has the highest melting point."

- **Analysis:** Thorium is known to have the highest melting point among all actinoids. The melting points of actinoids generally increase from actinium (Ac) to thorium (Th) and then decrease for heavier actinoids. Therefore, this statement is **correct**.

### Step 2: Evaluate Statement 2
**Statement 2:** "Th has the largest size among actinoids."

- **Analysis:** The size of the actinoids decreases as we move from thorium to the heavier actinoids due to a phenomenon known as actinoid contraction. This contraction occurs because of the poor shielding effect of the f-electrons, which leads to a stronger effective nuclear charge felt by the outer electrons. As a result, thorium, being the lightest actinoid, indeed has the largest atomic size among the actinoids. Therefore, this statement is also **correct**.

### Step 3: Determine the Relationship Between the Statements
- Both statements are correct; however, they are not directly related to each other. The fact that thorium has the highest melting point does not explain why it has the largest size.

### Conclusion
- **Final Evaluation:** Both Statement 1 and Statement 2 are true, but Statement 2 does not provide a correct explanation for Statement 1. Thus, the correct conclusion is that both statements are true, but they are independent of each other.

### Answer
Both statements are true, but Statement 2 is not a correct explanation of Statement 1.

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