Which of the following elements can be involved in `p pi- d pi` bonding ?

Options

A. Carbon
B. Nitrogen
C. Phosphorus
D. Boron

Answer

To determine which of the given elements can be involved in pπ-dπ bonding, we need to analyze the elements listed: carbon, nitrogen, phosphorus, and boron.

### Step-by-Step Solution:

1. **Identify the Period of Each Element**:
- Carbon (C) is in the 2nd period.
- Nitrogen (N) is in the 2nd period.
- Boron (B) is in the 2nd period.
- Phosphorus (P) is in the 3rd period.

2. **Understand pπ-dπ Bonding**:
- pπ-dπ bonding occurs when there is overlap between p orbitals of one atom and d orbitals of another atom.
- This type of bonding can only occur in elements that have accessible d orbitals, which are present in the third period and beyond.

3. **Analyze the Elements**:
- The 2nd period elements (C, N, B) do not have d orbitals. Therefore, they cannot participate in pπ-dπ bonding.
- Phosphorus, being a 3rd period element, has d orbitals available for bonding.

4. **Conclusion**:
- Among the given options, only phosphorus (P) can participate in pπ-dπ bonding due to the presence of d orbitals.

### Final Answer:
- The element that can be involved in pπ-dπ bonding is **Phosphorus (P)**.