History of the atom

Democritus

400 BCE

Democritus is a Greek philosopher who became first to suggest atoms. He also suggested that all matter consists of tiny, indivisible particles

John Dalton

1803

John Dalton is a English meteorologist and chemist who explored modern atomic theory. Dalton claimed that atoms of different elements vary in size and mass and he believed that each element had their own kind of atoms.

Dmitri Mendeleev

1869

Dmitri Mendeleev is best known for his work on the periodic law and he created the first periodic table. The Periodic Law states that "when elements are arranged according to their atomic number, elements with similar properties will appear at regular intervals."

Eugene Goldstein

1886

Eugene Goldstein is a German physicist who is known for his work on electrical phenomena in gases and on cathode rays. He also contributed greatly to the study of cathode rays. In 1876 he showed that these rays could cast sharp shadows.

J.J. Thomson

1897

Thompson is a English physicist who helped revolutionize the knowledge of atomic structure by his discovery of the electron.He originally called Electrons, corpuscles. He discovered it in a result of attempting to solve a long standing controversy regarding the nature of cathode rays.

Ernest Rutherford

1911

Ernest Rutherford is a new Zealand physicist discovered the nucleus of the atom. His model described the atom as a tiny, dense and positively charged core called a nucleus. All the mass is concentrated around the light which is called electrons.

Niels Bohr

1913

Niels Bohr is a Danish physicist who discovered the atomic theory. He was the first that incorporated quantum theory too. The Bohr model described the properties of atomic electrons in terms of a set of allowed possible values

Max Planck

1918

Max Planck is a German theoretical physicist who started the quantum theory. His theory changed our understanding of atomic and subatomic processes.

Robert Millikan

1923

Robert Millikan is an American physicist, who believed that the electric charge was carried by a single electron. He tried to experiment with water but that didn't work so he used oil. In the end he studied the elementary electronic charge and the photoelectric effect.

James Chadwick

1923

James Chadwick is a English physicist who studied the transmutation of elements, the proton, the nucleus of the hydrogen atom, as a constituent of the nuclei of other atoms.

Werner Heisenberg

1925

Werner Heisenberg is a German physicist and philosopher who discovered a way to formulate quantum mechanics in terms of matrices. He made some important contributions to the theories of , the atomic nucleus,cosmic rays, and subatomic particles.

Erwin Schrodinger

1933

Erwin Schrodinger is an Austrian theoretical physicist who contributed to the wave theory of matter and to other fundamentals of quantum mechanics.