The Atomic Theory

Leucippus

465 BCE

Is thought to be the mentor of Democritus, and the one that created the atomic theory. Also thought to had been a student of Zeno. He came up with this theory approximatelly on 465 BCE, the theory stated that the universe consisted on two elements, the atom and the void.

Democritus (460 BCE - 370 BCE)

445 BCE

Democritus was a Greek philosopher, he studied natural philosophy and geometry. His mentor was Leucippus, believed to have created the atomic theory. Democritus adopted the theory and studied it. This was his atomic theory: All matter consist of atoms, atoms are indestructible, atoms are solid but invisible, atoms are homogeneous, atoms differ in size, shape, mass, position and arrangement depending on the state of matter.

John Dalton (1766 - 1844)

1786

He is known better because of his studied in color blindness called daltonism in his honor, and for proposing the modern atomic theory. He made lots of proposals for this theory, like the rule: if atoms combine in only one ratio, it must be a binary one.

Thomas Thomson (1773 - 1852)

1793

Thomas Thomson was an important person in the history of the atomic theory, he helped spread Dalton's atomic theory. Like in one of his books were he explains how volumes of different gases react in a way, that supported the atomic theory.

Eugen Goldstein (1850 - 1930)

1870

Goldstein discovered the anode rays, and is sometimes credited for discovering the proton. Goldstein studied lot's of types of rays, he studied the anode, cathode, and canal rays.Working with the anode rays (composed of protons), Goldstein worked with protons, that's why it's sometimes acredited with that discovery.

Joseph John Thomson (1856 - 1940)

1876

He was an English physicist that got a Nobel prize because of the discovery of the electron, and the discovery of the first subatomic particle. He also worked on the conduction of electricity on gases.

Wilhelm Wien (1864 - 1928)

1884

German physicist who used theories about heat and electromagnetism to deduce Wien's displacement law, this was fundamental for quantum mechanics. Wien discovered in one of his experiments the proton.

Ernest Rutherford (1871 - 1937)

1891

Rutherford was an excellent scientist, helping others and discovering lot's of new things. One of his best achievements was discovering that an atom had a nucleus and that nearly it's total mass was concentrated on it, developing the nuclear model.

Niels Bohr (1885 - 1962)

1905

Bohr developed the Bohr model of the atom, he proposed that the energy level of electrons were discrete, and that electrons revolve in stable orbits around the nucleus but can jump from one orbit to another. He also made great contributions to the understanding of quantum theory.

James Chadwick (1891 - 1974)

1911

He was an English physicist who was awarded a Nobel Prize for discovering the neutron, this also inspired the US government in creating the atomic bomb.