-
300
Disagreeing to the Atom Theory
Aristotle didn't believe that atoms existed. He thought that everything and everyone was made up of the natural elements in the earth such as water and fire. -
400
Discovery of the Atom
Democritus discovered the idea of molecules that everything is made of. This occured in 400 B.C. -
Dalton's Theory
Dalton believes that mass is based upon small spherical atoms. -
Discovery of Thallium (element)
Crookes discovers the element ,thallium, using the crookes tube. -
First Periodic Table
Mendeleev creates the first organized periodic table. -
Discovery of the Electron
J. J. Thomson discovered the electron using cathode rays with the Crookes Tube. -
Discovery of the Proton
Rutherford discovers a positive force inside the nucleus of the atom. -
Discovery of the Neutron
Chadwick discovers the neutron after noticing a strange amount of mass that protons and electrons were not taking up. -
Period: to
Contributions to Chemistry
