Which of the following is not involved in `dpi -dpi `overlap:

Options

A. `N_(2)`
B. As
C. `P_(4)`
D. Bi

Explanation

To solve the question regarding which of the following is not involved in dπ-dπ overlap, we need to analyze the electronic configurations of the given options and identify whether they contain d orbitals.

### Step-by-Step Solution:

1. **Understanding dπ-dπ Overlap**:
- dπ-dπ overlap occurs between the d orbitals of two atoms. For this overlap to take place, both atoms must have d orbitals available.

2. **Analyzing the Options**:
- We have four options to consider: N₂, As, B₄, and Bi.

3. **Option 1: N₂ (Nitrogen)**:
- The electronic configuration of nitrogen (N) is 1s² 2s² 2p³.
- Nitrogen does not have any d orbitals because it is in the second period of the periodic table. Therefore, N₂ does not participate in dπ-dπ overlap.

4. **Option 2: As (Arsenic)**:
- The electronic configuration of arsenic (As) is [Ar] 4s² 3d¹⁰ 4p³.
- Arsenic has d orbitals (3d) and can participate in dπ-dπ overlap.

5. **Option 3: B₄ (Boron)**:
- The electronic configuration of boron (B) is 1s² 2s² 2p¹.
- Boron does not have d orbitals as it is also in the second period. Therefore, B₄ does not participate in dπ-dπ overlap.

6. **Option 4: Bi (Bismuth)**:
- The electronic configuration of bismuth (Bi) is [Xe] 6s² 4f¹⁴ 5d¹⁰ 6p³.
- Bismuth has d orbitals (5d) and can participate in dπ-dπ overlap.

7. **Conclusion**:
- The elements that do not have d orbitals and cannot participate in dπ-dπ overlap are N₂ and B₄. However, since the question asks for one option, we focus on N₂ as the primary answer.

### Final Answer:
The option that is not involved in dπ-dπ overlap is **N₂**.