Periodic Table Development

Events

Produce of a Table

1864

Dmitri Mendeleev produced a table based on atomic weights but arranged 'periodically' with elements with similar properties under each other. His Periodic Table included the 66 known elements organized by atomic weights.

Discovery Of Noble Gases

1894

William Ramsay discovered the Noble Gases.

Radium and Polonium

1898

Marie and Pierre Curie isolated radium and polonium from pitchblende.

Atoms development

1900

Ernest Rutherford discovered the source of radioactivity as decaying atoms

'Periodic Law'

1913

Henry Moseley determined the atomic number of each of the elements and modified the 'Periodic Law'.

Elements after Uranium

1940

Glenn Seaborg synthesised transuranic elements (the elements after uranium in the periodic table)

Identify Neptunium

1940

Edwin McMillan and Philip H. Abelson identify neptunium, the lightest and first synthesized transuranium element, found in the products of uranium fission.