In which year did Henry Moseley use X-rays to measure the wavelength of elements, and correlate these measurements with their atomic numbers?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 1913
Henry Moseley conducted his groundbreaking experiment in 1913. He used X-ray spectroscopy to measure the wavelengths of X-rays emitted by different elements.
Moseley discovered a clear relationship between the frequency of X-rays and the atomic number of the element, rather than its atomic mass. This finding corrected errors in the Mendeleev’s periodic table and established that atomic number, not atomic weight, determines an element’s properties.
His work led to the modern arrangement of the Periodic Table based on atomic numbers. Tragically, Moseley died young at age 27 during World War I in 1915, cutting short a brilliant scientific career. His research laid the foundation for identifying missing elements and understanding atomic structure more precisely.