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Johann Dobereiner
Classified Some elements into groups of free, which he called triads. The element in a triad had similar chemical properties and orderly physical properties -
Law of octaves
John Newlands suggested the Law of Octaves -
John Newlands
Suggested that elements can be arranged in octaves because he noticesd after arranging the elements in order of increaing atomic mass that certain properties repeated every 8th element -
Dimitri Mendeleev and Lothar Meyer
Dimitri Mendeleev publised a table of elements organised by increasing atomic mass. At the same time Lothar Meyer organised a table by the increaing atomic mass -
Mendeleev discovey of unknown elements
His table was generally accepted as unknown elements between 1974 and 1885 -
Law of Octaves Proved Wrong
The law of Octaves was proved wrong as the octaves failed beyond calcium -
Henry Moseley
Through his work with X-Rays he dtermined the actual nuclear charge of the -
Glenn T Seaborg
Co discover 10 new elements he moved 14 elements out of the main body and moved them under the Lanthanide series to be known as the Actinide Series