Assertion (A): Nitrogen has diamagnetic in nature.
Reason (R): Nitrogen has chemically active element.

Options

A. Both A and Rare true and R is the correct ex planation of A
B. Both A and Rare true but R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true

Explanation

To analyze the assertion and reason given in the question, we will go through the following steps:

### Step 1: Understanding the Assertion
The assertion states that "Nitrogen has diamagnetic nature."
- **Explanation**: Diamagnetic substances are those that do not have unpaired electrons in their atomic or molecular orbitals. In the case of nitrogen (N2), it has a total of 14 electrons (7 from each nitrogen atom). When we fill these electrons according to the Molecular Orbital Theory (MOT), we find that all electrons are paired.

### Step 2: Confirming the Diamagnetic Nature
Using the Molecular Orbital Diagram for N2:
- The filling order is:
- σ1s (2 electrons)
- σ*1s (2 electrons)
- σ2s (2 electrons)
- σ*2s (2 electrons)
- π2px (2 electrons)
- π2py (2 electrons)
- σ2pz (2 electrons)
- Total: 14 electrons, with all electrons paired. Therefore, N2 is indeed diamagnetic.

### Step 3: Understanding the Reason
The reason states that "Nitrogen is a chemically active element."
- **Explanation**: While nitrogen is essential for many chemical reactions, the N2 molecule is quite stable due to its strong triple bond. This makes it relatively inert under standard conditions, requiring significant energy to break the bond for reactions to occur.

### Step 4: Conclusion
- The assertion (A) is true because nitrogen (N2) is diamagnetic.
- The reason (R) is false because nitrogen (as N2) is not chemically active; it is chemically inert due to its strong triple bond.

### Final Answer
- Assertion (A) is true, and Reason (R) is false.