feb 1, 1802 - 1803 AD: John Dalton, a chemist and schoolteacher performed various experiments related to atoms such as mixing gases and explaining compounds. In 1803, he came up with the very first atomic theory: Atoms of the same element are identical, Atoms of different elements have different weights and chemical properties, compounds are formed when elements are combined and atoms cannot be created or destroyed. He also created the very first model of what an atom would look like.
Added to timeline:
Date:
feb 1, 1802
Now
~ 223 years ago