Models of the Atom

Erwin Schrödinger (1926)

Erwin Schrödinger develops mathematical equations to describe the motion of electrons in atoms. His work leads to the electron cloud model. (The nucleus contains protons and neutrons; The electron cloud is a visual model of the probable locations of electrons in an atom. The probability of finding an electron is higher in the denser regions of the cloud)

Louis de Broglie (1923)

French physicist Louis de Broglie proposes that moving particles like electrons have some properties of waves. Within a few years, experimental evidence supports the idea.

Hantaro Nagaoka (1904)

Hantaro Nagaoka, a Japanese physicist, suggests that an atom has a central nucleus. Electrons move in orbits like the rings around Saturn.

Niels Bohr (1913)

In Niels Bohr's model, the electron moves in a circular orbit at fixed distances from the nucleus. (An electron can gain or lose energy by changing its orbit; electron; nucleus)

J.J. Thomson (1897)

J.J. Thomson, a British scientist, discovers the electron. The later leads to his "plum-pudding" model. He pictures electrons embedded in a sphere of positive electrical charge. (Sphere with positive charge throughout; Negatively charged particle (electron))

James Chadwick (1932)

James Chadwick, an English physicist, confirms the existence of neutrons, which have no charge. Atomic nuclei contain neutrons and positively charged protons.

John Dalton (1803)

John Dalton pictures atoms as tiny, indestructible particles, with no internal structure. (Tiny, solid sphere)

Ernest Rutherford (1911)

New Zealand physicist Ernest Rutherford finds that an atom has a small, dense, positively charged nucleus. Electrons move around the nucleus. (Path of moving electron; Nucleus)