Atomicity of helium is ___

Explanation

To find the atomicity of helium, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Atomicity**:
- Atomicity refers to the total number of atoms present in a molecule of a substance. It can be defined for both elements and compounds.

2. **Identify Helium**:
- Helium is a chemical element with the symbol He. It is a noble gas and is known for being monoatomic.

3. **Determine the Atomicity of Helium**:
- Since helium exists as individual atoms and does not form diatomic or polyatomic molecules, its atomicity is simply the number of atoms in a single helium atom.

4. **Conclude the Atomicity**:
- Therefore, the atomicity of helium is 1, indicating that it is a monoatomic gas.

### Final Answer:
The atomicity of helium is **1**.

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