Which noble gas is not present in the atmosphere?

Explanation

**Step-by-Step Solution:**

1. **Identify the Noble Gases**: The noble gases include Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn).

2. **Examine Their Presence in the Atmosphere**:
- Helium is found in the atmosphere in trace amounts.
- Neon is also present in the atmosphere.
- Argon is the most abundant noble gas in the atmosphere, making up about 0.93% of the air.
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