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Döbereiner's Triads
Johann Döbereiner proposed triads that were an early attempt at organizing the chemical elements by certain physical properties. He noted that there were triads of elements that showed similar chemical properties. He also noted that other properties of the elements followed trends in which the value of the middle element of the triad was in between those of the end members. -
Chancoutios' Telluric Spiral
Aleandre Beguyer de Chancoutios arranged a spiral graph that ordered the elements by their atomic weight. -
Newland's Law of Octaves
John Newlands arranged the known elements by their atomic weight, and noted that every eight element had similar properties. -
Mendeleev's Periodic Table
Dmitri Mendeleev arranged the 63 known elements into a periodic table based on atomic mass. In this table, he left space for undiscovered elements, and predicted the properties of three then unknown elements. His table, however, did not include the noble gases, which were at the time unknown. -
Meyer's Periodic Table
Julius Lothar von Meyer created a periodic table by atomic weight. His original table was created in 1864, but he revised it in 1870. While a good model, Mendeleev's Periodic Table was better structured. -
Noble Gases Discovered
William Ramsay discovered the noble gases and realised that they represented a new group in the periodic table. -
Moseley's Periodic Law
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. -
Modern Periodic Table
Glenn Seaborg artificially produced heavy mass elements such as neptunium. These new elements were part of a new block of the periodic table called ‘actinides’. This updated the periodic table to where it is today.