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Dalton 1803 A.D.
He discovered that the atoms were tiny invisible, indestructable particles. Used observation evidence to guide his theories, hyptheses & particles Nicknamed - Billiard Ball model because he thought that the atom looked like billiard ball from pool www.britannica.com -
Thomson 1898 A.D.
Discoreved that electricity passing through gas called the gas to give off particles that were to small to be atoms. Used the property of cattode rays. Nicknames - plum pudding & raisin bread he believed it was just a small sphere web.lemoyne.edu -
Rutherford 1911 A.D.
A diffuse cloud of negatively charged electrons surrounding small ,dense, positively charge nucleus. He used the gold foil on Thomson atom. Most empty space and that its positive charges concentration dense mass at its core. www.ium.edu -
Bohr 1913 A.D.
Electrons can only gain and lose energy by jumping from one allowed orbit to another. He used the Planck relation The electrons could only have certain classical motion; small positively charged nucleus orbited by negatively charged electrons. www.chemistry.about.com -
Heisenberg and Schrodinger 1927 A.D.
Neutrons electron cloud. The Heisenberg uncertainity relationship mathmatical equation. Round necleus with protons & neuutrons surrounded by electron cloud www.google.com -
Democritus 400 B.C.
Proposed that matter is made of tiny particle called atoms also everything is made of matter. Relied on rational pressure rather than experimental obserrvation. He believed that atoms of different elements may have different shapes www.nobeliefs.com
