The following element doesn't have allotropes

Options

A. N
B. P
C. As
D. S

Answer

To determine which of the following elements does not have allotropes, we will analyze each option provided: nitrogen, phosphorus, arsenic, and sulfur.

### Step-by-Step Solution:

1. **Understanding Allotropes**:
Allotropes are different forms of the same element, where the atoms are arranged differently. This can lead to different physical and chemical properties.

2. **Analyzing Nitrogen**:
- Nitrogen (N) is a diatomic molecule (N₂) in its most stable form.
- It does not exist in any other structural forms or allotropes.
- **Conclusion**: Nitrogen does not have allotropes.

3. **Analyzing Phosphorus**:
- Phosphorus (P) has several allotropes, including white phosphorus, red phosphorus, black phosphorus, violet phosphorus, and scarlet phosphorus.
- **Conclusion**: Phosphorus has allotropes.

4. **Analyzing Arsenic**:
- Arsenic (As) has three allotropes: yellow arsenic, black arsenic, and gray arsenic.
- The gray allotrope is the most stable form.
- **Conclusion**: Arsenic has allotropes.

5. **Analyzing Sulfur**:
- Sulfur (S) has multiple allotropes, including rhombic sulfur (alpha) and monoclinic sulfur (beta), among others.
- **Conclusion**: Sulfur has allotropes.

6. **Final Conclusion**:
- After analyzing all the elements, we find that nitrogen is the only element among the options that does not have allotropes.

### Answer:
**The element that does not have allotropes is nitrogen (N).**

---