How many elements are solid non-metals among the following elements ?
Carbon, nitrogen, chlorine, helium, phosphorus, sulphur and iodine

Explanation

To determine how many elements are solid non-metals among the given elements (Carbon, Nitrogen, Chlorine, Helium, Phosphorus, Sulfur, and Iodine), we will analyze each element based on its physical state at room temperature and its classification as a non-metal.

### Step-by-Step Solution:

1. **Identify the Elements**: We have the following elements to consider:
- Carbon (C)
- Nitrogen (N)
- Chlorine (Cl)
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