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Alexandre-Emile Béguyer de Chancourtois
Plotted the atomic weights of elements on paper tape and wound them, spiral like, around a cylinder. The design put similar elements onto corresponding points above and below one another. He called his model the telluric helix or screw. -
Alexandre-Emile Béguyer de Chancourtois
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Period: to
Alexandre-Emile Béguyer de Chancourtois
Plotted the atomic weights of elements on paper tape and wound them, spiral like, around a cylinder. The design put similar elements onto corresponding points above and below one another. He called his model the telluric helix or screw. -
Dmitri Mendeleev
Produced a periodic table based on atomic weights but arranged ‘periodically’. Elements with similar properties appeared under each other. Gaps were left for yet to be discovered elements. -
Dmitri Mendeleev
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Period: to
Dmitri Mendeleev
produced a periodic table based on atomic weights but arranged ‘periodically’. Elements with similar properties appeared under each other. Gaps were left for yet to be discovered elements. -
William Ramsay
Discovered the noble gases and realised that they represented a new group in the periodic table. The noble gases added further proof to the accuracy of Mendeleev’s table. -
William Ramsay
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Henry Moseley
Determined the atomic number of each of the known elements. He realised that, if the elements were arranged in order of increasing atomic number rather than atomic weight, they gave a better fit within the ‘periodic table’. -
Henry Moseley
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Period: to
Henry Moseley
Determined the atomic number of each of the known elements. He realised that, if the elements were arranged in order of increasing atomic number rather than atomic weight, they gave a better fit within the ‘periodic table’. -
Glenn Seaborg
proposed an ‘actinide hypothesis’ and published his version of the table in 1945. The lanthanide and actinide series form the two rows under the periodic table of elements. -
Glenn Seaborg
