Atomic Theory People

Erwin Schrödinger

Derived an equation that showed how electrons travel around the nucleus as a wave.

Aristotle

Thought matter was made up of four elements: earth, fire, water, and air.

Sir William Crookes

Discovered negatively-charged particles in the green flash of a cathode ray tube.

Henry Moseley

Discovered that atoms of each element have different numbers of protons.

James Chadwick

Discovered the neutron.

Ernest Rutherford

Discovered the nucleus using the gold foil experiment.

John Dalton

Expanded on the work of Democritus; came up with six-part atomic theory.

Democritus

First thought matter was made up of tiny particles called atoms.

Robert Millikan

Found the charge and mass of an electron using the oil-drop experiment.

Louis de Broglie

Proposed that electrons have wave-like behavior.

Niels Bohr

Proposed that electrons orbit the nucleus in specific paths, like planets orbit the sun.

Albert Einstein

Proposed that light has a dual nature; stated that light can be thought of as a beam of photons.

Max Planck

Proposed that matter can gain or lose energy only in small, specific amounts (called quanta).

J.J. Thomson

Proposed the plum pudding model of the atom.

Ernest Rutherford

Discovered the proton.

J.J. Thomson

Determined that the mass of an electron was much less than that of a hydrogen atom; credited with discovering the electron.