History of Atomic Theory as told by Thomas Jefferson

Democritus

340

Democritus Atom Democritus claimed that everything is made out of atom. They are physically indivisble and indestructible.

John Dalton

Dec 9, 1803

Dalton's atomic theory Dalton's theory is that all matter is made of atoms. Atoms are indivisble. A chemical reactipn is a rearrangment of atoms.

J.J. Thomson

May 10, 1897

J.J. Thomson Thomson founded the electron in 1897.He found out atoms had smaller particles. He used a cathode ray tube. He later found out that atoms were made of protons, neutrons, and electrons.

Ernest Rutherford.

Aug 10, 1911

Rutherford Rutherford published his theory that the atom has a central positive nucleus and negative electrons. He put out gold foil. 1 of 8000 particles went throught, thus saying that the atom is mostly empty.

James Chadwick

Oct 27, 1932

James Chadwick Chadwick predicted there would be a neutron. He established that the number of protons is the atomic number.

Niels Bohr

Oct 5, 1937

Niels Bohr Niels Bohr won a Nobel in 1922. He later was the first one to discover that electrons travel in different orbit around the nucleus.