STATEMENT-1 : Out of all actinoids , Th has highest melting point .
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, we need to evaluate both Statement-1 and Statement-2 regarding thorium (Th) and its properties among the actinoids.

### Step-by-Step Solution:

**Step 1: Understand the Actinoids**
- The actinoids are a series of elements from actinium (Ac) to lawrencium (Lr) in the periodic table. They are known for their complex electron configurations and varying physical and chemical properties.

**Step 2: Evaluate Statement-1**
- **Statement-1:** "Out of all actinoids, Th has the highest melting point."
- Thorium (Th) does have a relatively high melting point compared to other actinoids. In fact, thorium has one of the highest melting points among the actinoids, which is approximately 1,750 °C.
- Therefore, Statement-1 is **correct**.

**Step 3: Evaluate Statement-2**
- **Statement-2:** "Th has the largest size among actinoids."
- The size of the actinoids generally decreases as we move from actinium (Ac) to lawrencium (Lr) due to the increasing nuclear charge which pulls the electrons closer to the nucleus.
- Thorium, being one of the first elements in the actinoid series, does have a larger atomic radius compared to the later actinoids. Thus, it can be considered to have one of the largest sizes among the actinoids.
- Therefore, Statement-2 is also **correct**.

**Step 4: Conclusion**
- Both statements are correct. Thorium has the highest melting point among the actinoids and also has one of the largest atomic sizes in this series.

### Final Answer:
Both Statement-1 and Statement-2 are correct.

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