HISTORY

• The periodic table was noticed early by people, and Greek thinkers, about 400BC.
• They used the words "element', and `atom' to describe the differences and smallest parts of matter.
• These ideas survived for 2000 years while concepts such as `Elements' of Earth, Fire, Air, and Water to explain `world stuff' came and went.
• In the early 1800's Dobereiner, a scientist, noted that similar elements often had relative atomic masses, and DeChancourtois, another scientist, made a cylindrical table of elements to display the periodic reoccurrence of properties.
• Cannizaro determined atomic weights for the 60 or so elements known in the 1860s, then a table was arranged by Newlands, with the elements given a serial number in order of their atomic weights, beginning with Hydrogen.

DeChancourtois	Dobereiner