Scientists

Scientists

J. J. Berzelius

Created the modern symbols of elements.

Democritus

Greek philosopher who proposed that matter is composed of invisible particles.

Alchemy

First to switch from through to observation.

John Dalton

Proposes law of Multiple Proportions and re-proposes atomic theory.

Antoine Lavoisier

Propses law of conservation of mass

Joseph Proust

Proposes law of constant Proportions

J. J. Thomson

Discovered that atoms are made up of smaller particles; used Cathode Ray Tube; discovered electrons; mass of electrons.

Plum Pudding Model

A model of the atom with positive and negative particles, making an atom neutral.

Robert A. Millikan

Determined the charge of an electron.

Ernest B Rutherford

Discovered the nucleus using alpha particles; discovered proton.

Neils Bohr

Proposed the Bohr model

Chadwick

Discovered the neutron.

Willard Libby

Radiocarbon Dating