John Dalton is best known for his pioneering work in the development of modern atomic theory in 1802.

In 1886, Goldstein concluded that in addition to the electrons, or cathode rays, that travel from the negatively charged cathode toward the positively charged anode, there is another ray that travels in the opposite direction, from the anode toward the cathode.

J.J. Thomson’s fame derives primarily from his discovery of the electron in 1897.

Max Planck made many contributions to theoretical physics and attained his fame via his role as originator of the quantum theory in 1900. This theory revolutionized our understanding of atomic and subatomic processes, it is one of the fundamental theories of 20th-century physics, and has led to industrial and military applications that affect every aspect of modern life.

Albert Einstein discovered the theory of relativity in 1905. He also contributed to Chemistry in numerous other ways.

Bohr concentrated the majority of his effort on researching the structure of the atom, and in 1913 he completed his theory of atomic structure.

In 1913, Henry Moseley developed the application of X-ray spectra to study atomic structure; Moseley's discoveries resulted in a more accurate positioning of elements in the Periodic Table by closer determination of atomic numbers.

In 1921, Robert Millikan proved that this radiation is indeed of extraterrestrial origin, and he named it “cosmic rays.”

Ernest Rutherford discovered alpha and beta rays, set forth the laws of radioactive decay, and identified alpha particles as helium nuclei in 1921.

French quantum physicist Louis de Broglie introduced his theory of particle-wave duality in 1924.

Werner Heisenberg is best known for the development of the matrix mechanics formulation of quantum mechanics in 1925 and for asserting the uncertainty principle in 1926, although he also made important contributions to nuclear physics, quantum field theory and particle physics.

James Chadwick discovered the neutron in 1932.

Erwin Schrödinger was an Austrian theoretical physicist who achieved fame for his contributions to quantum mechanics by philosophical issues raised by his 1935 “Schrödinger's cat” thought experiment perhaps remain his best known legacy, but the Schrödinger equation, which he formulated in 1926 to describe the quantum state of a system, is his most enduring achievement at a more technical level.