An element, X, have three isotopes X 20, X 21 and X 22. The percentage abundance of X 20is 90% and its average atomic mass of the element is 20.11. Th...

Question

An element, X, have three isotopes X 20, X 21 and X 22. The percentage abundance of X 20is 90% and its average atomic mass of the element is 20.11. The percentage abundance of X 21 should be

**Options:**
- **A.** [object Object]
- **B.** [object Object]
- **C.** [object Object]
- **D.** [object Object]

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**Difficulty:** EASY | **Chapter:** Mole concept | **Topic:** Law of chemical combination, atomic & molecular mass, mole concept, calculations

Accepted Answer

## ✅ Correct Answer: **A**

### 📖 Detailed Explanation:
This question uses atomic structure & atomic mass. Relate mass, moles and number of particles using the mole concept and basic stoichiometry; doing the algebra gives the value listed in option A.

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An element, X, have three isotopes X 20, X 21 and X 22. The percentage abundance of X 20is 90% and its average atomic mass of the element is 20.11. Th...

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