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Period: to
Antoine Lavoisier
Recognised and named Oxygen and Hydrogen, predicted the existence of Silicon and proposed and then proved that Sulfur was an element and not a compound. -
Johann Wolfgang Döbereiner
Reported trends in selected groups of elements and that elements in those groups had similar atomic mass -
Alexandre-Émile Béguyer de Chancourtois
Proposed the classification of elements in terms of their atomic weights. -
John Newlands
First to organise a periodic table of elements in order of relative atomic mass -
Julius Lothar Meyer
Classified elements into six families by valence. Created the earlier version of the periodic table that was then improved by Mendeleev. -
Dmitri Mendeleev
Created a 'future' periodic table that predicted the undiscovered elements by looking at the properties of know elements -
Henry Moseley
Proposed that the periodic table should be sorted by atomic number rather than atomic mass. -
Period: to
Glenn T. Seaborg
Discovered/co-discovered 10 elements. Also discovered more than 100 atomic isotopes for already discovered elements.
