Select the element which does not form double bond

Options

A. Nitrogen
B. Sulphur
C. Silicon
D. Phosphorus

Explanation

To determine which element does not form a double bond, we can analyze the bonding behavior of the given elements: Nitrogen, Sulfur, Silicon, and Phosphorus.

### Step-by-Step Solution:

1. **Understanding Double Bonds**: A double bond occurs when two pairs of electrons are shared between two atoms. This typically happens between atoms that are small in size and can effectively overlap their orbitals.

2. **Analyzing Nitrogen**:
- Nitrogen (N) can form a triple bond in N₂ (two nitrogen atoms sharing three pairs of electrons).
- It can also form double bonds, such as in nitrogen oxides (e.g., NO, N₂O).
- **Conclusion**: Nitrogen can form double bonds.

3. **Analyzing Sulfur**:
- Sulfur (S) can form double bonds, as seen in sulfur dioxide (SO₂), where sulfur shares two pairs of electrons with oxygen.
- **Conclusion**: Sulfur can form double bonds.

4. **Analyzing Silicon**:
- Silicon (Si) is larger in size compared to nitrogen and sulfur. The larger atomic radius leads to poorer overlap of orbitals, making it less favorable for silicon to form double bonds.
- Silicon typically forms single bonds, such as in silicon dioxide (SiO₂), where it forms single bonds with oxygen.
- **Conclusion**: Silicon does not form double bonds.

5. **Analyzing Phosphorus**:
- Phosphorus (P) can also form double bonds, as seen in compounds like phosphorus pentachloride (PCl₅) and phosphoric acid (H₃PO₄), where it can share multiple pairs of electrons.
- **Conclusion**: Phosphorus can form double bonds.

6. **Final Conclusion**: Among the elements analyzed, Silicon is the element that does not form double bonds.

### Answer:
**Silicon** does not form double bonds.

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