A: Mn shows exceptional M.P. in 3d series
R: Its outer configuration is `4s^(2) 3d^(5)`

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion.
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion.
C. If Assertion is true statement but Reason is false.
D. If both Assertion and Reason are false statements.

Answer

To solve the question regarding the assertion and reason provided, we will follow these steps:

### Step 1: Understand the Assertion
The assertion states that manganese (Mn) shows an exceptional melting point in the 3d series.

### Step 2: Analyze the Reason
The reason given is that manganese's outer electronic configuration is \(4s^2 3d^5\).

### Step 3: Investigate the Melting Point of Manganese
Manganese is known for having a high melting point compared to other transition metals in the 3d series. This is due to the strong metallic bonding that arises from its electronic configuration.

### Step 4: Examine the Electronic Configuration
The electronic configuration \(4s^2 3d^5\) indicates that manganese has a half-filled \(3d\) subshell. Half-filled subshells are particularly stable due to symmetry and exchange energy, which contributes to stronger metallic bonding.

### Step 5: Relate Electronic Configuration to Melting Point
The presence of a half-filled \(3d\) subshell means that the \(3d\) electrons are more tightly held by the nucleus. This tight binding reduces the delocalization of electrons, which in turn enhances the metallic bonding strength.

### Step 6: Conclusion on Assertion and Reason
Since manganese does indeed have a high melting point due to its stable electronic configuration, both the assertion and reason are true. Furthermore, the reason correctly explains why manganese has an exceptional melting point.

### Final Answer
Both the assertion and reason are true, and the reason is the correct explanation of the assertion.