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what was Henry Moseley's contribution to the periodic table?
In 1914 Henry Moseley found a relationship between an element's X-ray wavelength and its atomic number (Z), and therefore resequenced the table by nuclear charge rather than atomic weight. [ Before this discovery, atomic numbers were just sequential numbers based on an element's atomic weight. Moseley's discovery showed that atomic numbers had an experimentally measurable basis. Thus Moseley
placed argon (Z=18) before potassium (Z=19) based on their X-ray wavelengths, despite the fact that argon has a greater atomic weight (39.9) than potassium (39.1). The new order agrees with the chemical properties of these elements, since argon is a noble gas and potassium an alkali metal. Similarly, Moseley placed cobalt before nickel, and was able to explain that tellurium occurs before iodine without revising the experimental atomic weight of tellurium (127.6) as proposed by Mendeleev. Moseley's research also showed that there were gaps in his table at atomic numbers 43 and 61 which are now known to be Technetium and Promethium, respectively, both radioactive and not naturally occurring. Following in the footsteps of Dmitri Mendeleev, Henry Moseley also predicted new elements. ]
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what was Henry Moseley's contribution to the periodic table?
Weegy: Henry Gwyn Jeffreys Moseley (23 November 1887 – 10 August 1915) was an English physicist. [ Moseley's outstanding contribution to the science of physics was the justification from physical laws of the previous empirical and chemical concept of the atomic number. This stemmed from his development of Moseley's law in X-ray spectra. Moseley's Law justified many concepts in chemistry by sorting the chemical elements of the periodic table of the elements in a quite logical order based on their physics. Moseley's law advanced atomic physics by providing the first experimental evidence in favor of Niels Bohr's theory, aside from the hydrogen atom spectrum which the Bohr theory was designed to reproduce. That theory refined Ernest Rutherford's and Antonius Van den Broek's model, which proposed that the atom contains in its nucleus a number of positive nuclear charges that is equal to its (atomic) number in the periodic table. This remains the accepted model today. Please also refer to Thank you for using Weegy ] (More)
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Asked 11/3/2011 9:33:07 PM
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what was Henry Moseley's contribution to the periodic table?
Weegy: The Researching around I would say discovery of the "atomic number" used for ordering the elements in the periodic table would probably be the answer. This is recorded as being in 1913. (More)
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Asked 11/3/2011 9:40:39 PM
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Asked 11/4/2011 6:41:57 AM
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Weegy: In the transition elements, electrons are usually added to the outer orbital, which is why these elements are also knows as the transition metals (More)
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Asked 11/4/2011 8:27:18 AM
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Weegy: As the nuclear charge increases across a period, the effective nuclear charge INCREASES (as the shielding of the outer electrons remains almost constant) pulling the electrons closer to the nucleus and DECREASING the size of the atom." (More)
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Asked 11/4/2011 8:36:00 AM
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