Ozone is an _____of oxygen.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks to fill in the blank with the correct term that describes ozone in relation to oxygen.

2. **Definition of Ozone**: Ozone is a molecule composed of three oxygen atoms, represented chemically as O₃.

3. **Concept of Allotropes**: Allotropes are different forms of the same element that exist in the same physical state. For example, carbon exists as graphite and diamond, and oxygen exists as O₂ (dioxygen) and O₃ (ozone).

4. **Identifying Ozone as an Allotrope**: Since ozone (O₃) is a different molecular form of oxygen (O₂), it qualifies as an allotrope of oxygen.

5. **Final Answer**: Therefore, the complete sentence is: "Ozone is an allotrope of oxygen."

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