Atomic number is the fundamental property of an element'. Write the name of the scientist who proved it by an X-ray experiment.

Options

A. a)Bohr
B. b)Newlands
C. c)Mendeleev
D. d)Moseley

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question states that the atomic number is a fundamental property of an element and asks for the name of the scientist who proved this through an X-ray experiment.

2. **Identifying Key Concepts**:
- The atomic number is the number of protons in the nucleus of an atom, which defines the element.
- The significance of the atomic number was established through experiments that demonstrated it as a more fundamental property than atomic mass.

3. **Historical Context**:
- The periodic table was initially organized by atomic mass by Dmitri Mendeleev. However, discrepancies arose because some elements did not fit well into this classification.

4. **Key Experiment**:
- In 1913, Henry Moseley conducted X-ray experiments that led to the conclusion that the atomic number, rather than atomic mass, should be the basis for the arrangement of elements in the periodic table.

5. **Conclusion**:
- The scientist who proved that the atomic number is a fundamental property of an element through X-ray experiments is **Henry Moseley**.

**Final Answer**: Henry Moseley

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