Atom Timeline

Solid Sphere Model

Atoms are like hard spheres; indivisible and everything is made of atoms. Created by John Dalton in 1803.

Plum Pudding Model

Atoms are a positively charged cloud containing tiny negatively charged particles (electrons). Discovered by JJ Thompson in 1904.

Nuclear Model

Atoms have a small positively charged center called a nucleus, with electrons moving around it. Discovered by Ernest Rutherford in 1911.

Gold Foil Experiment

An experiment that led to the discovery of the nucleus of the atom.

Planetary Model

Electrons exist at specific energy levels called orbitals, moving in patterns around the nucleus. Developed by Niels Bohr in 1913.

Quantum Model

Also known as the wave-mechanical model, where electrons travel as waves around the nucleus, not in circular orbits. Created by Erwin Schrodinger in 1926.