Atomic model

Democritus

Proposed that matter is made of tiny, indivisible particles called "atomos."

Aristotle

Rejected atomic theory, believing matter was continuous and made of four elements (earth, air, fire, water).

John Dalton

Created the first modern atomic theory with solid, indivisible spheres.

William Crookes

sub atomic

J.J. Thomson

Identified the electron and proposed the "plum pudding model."

Robert Millikan

Determined the charge of the electron with the oil drop experiment.

Ernest Rutherford

discovered the nucleus and protons

Niels Bohr

1913- discovered that electrons move around the nucleus in orbits called electron shells.

Louis de Broglie

All moving objects have wave-like behavior. Matter shows properties of both wave and particles

Werner Heisenberg

uncertainty principle

James Chadwick

Discovered the neutron