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Chemistry: Challenges and Solutions

Moseley and the Periodic Table (animation)

In 1913, British physicist Henry Moseley made careful measurements of x-ray spectra and correctly ordered the elements in the periodic table. Later it was confirmed that Moseley’s order was based on atomic number (the number of protons in the nucleus) rather than the method used before, atomic mass (the total number of protons and neutrons).

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Chemistry: Challenges and Solutions


Produced by the Harvard-Smithsonian Center for Astrophysics. 2014.
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