Assertion (A): Transition metals have low melting points.
Reason (R): The involvement of greater number of (n-1)d and ns electrons in the interatomic metallic bonding.

Options

A. Both A and Rare true and R is the correct explanation of A.
B. Both A and R are true but R is NOT the correct explanation of A.
C. A is true but R is false.
D. A is false and R is True

Explanation

To solve the question regarding the assertion and reason provided, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
**Assertion (A): Transition metals have low melting points.**

- Transition metals are known for their high melting points due to strong metallic bonding. The presence of partially filled d-orbitals allows for effective overlap of orbitals, leading to stronger bonds.
- Therefore, the assertion that transition metals have low melting points is **incorrect**.

### Step 2: Analyze the Reason
**Reason (R): The involvement of a greater number of (n-1)d and ns electrons in the interatomic metallic bonding.**

- Transition metals have a unique electronic configuration where the (n-1)d and ns electrons can participate in metallic bonding.
- The involvement of these electrons enhances the strength of metallic bonds. The more electrons that participate in bonding, the stronger the bonds become, resulting in higher melting points.
- Thus, the reason provided is **correct**.

### Step 3: Conclusion
- Since the assertion is incorrect and the reason is correct, we conclude that the correct relationship is that the assertion does not support the reason.
- Therefore, the answer to the question is that the assertion is false, but the reason is true.

### Final Answer
The assertion is incorrect, and the reason is correct. The correct option is **Option 4**.

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