jan 1, 1913 - Henry Moseley

Description:

English physicist.
He discovered the atomic number of each element using x-rays, which led to the more accurate organization of the periodic table.
In July 1913, a conversation with physicist Niels Bohr led to the suggestion that an element's atomic number could be determined by x-ray spectroscopy. In x-ray spectroscopy, electrons are fired at a metal plate, causing the atoms of metal to emit x-rays. The wavelength and frequency of these x-rays are then recorded.

Henry Moseley collected the x-ray spectra of a variety of elements and found that the frequency of x-ray radiation has a precise mathematical relationship with an element's atomic number. This relationship is now called Moseley's Law.

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