Periodic Table

Johann Dobereiner

Feb 1, 1829

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

Mar 2, 1838

John Newlands suggested the Law of Octaves

John Newlands

Mar 1, 1863

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

Mar 2, 1869

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

Mar 2, 1874

His table was generally accepted as unknown elements between 1974 and 1885

Law of Octaves Proved Wrong

Mar 2, 1898

The law of Octaves was proved wrong as the octaves failed beyond calcium

Henry Moseley

Mar 2, 1913

Through his work with X-Rays he dtermined the actual nuclear charge of the

Glenn T Seaborg

Mar 4, 1944

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