Atomic Model

Democritus

300

Democritus believed that all matter consisted of extremely small particles that could not be divided. He used discourse, which means they talked their way through different processes to get their model.

Aristotle

500

Aristotle did not think there was a limit to the number of times matter could be divided. Aristotle also talked his way through his ideas which was discourse.

John Dalton

Oct 28, 1803

Dalton studied the behavior of gasses in the air. He gathered evidence for the existence of atoms by measuring the mass of elements that combines to compound form. He noticed all compounds have somthing in common.

Eugen Goldstein

Nov 1, 1886

Goldstein discovered that atoms have positive charges. He used Helmholtz's investigation. He used dischared tubes to prove protons exist.

Joseph John Thomson

Oct 29, 1897

Thomson studied what happens when materials are rubbed together, Materials gain the ability to attract or repel other material. He used electric current to learn more about atoms. Thomson's experiment provided the first evidence that atoms are made of even smaller particles.

Hantoro Nagoaka

Oct 29, 1904

Nagoaka suggested that an atom has a central nucleus. He based his evidence off facts regarding Saturn's rings.

Ernest Ruthford

Oct 29, 1911

Ruthford discovered that uranium emits fast moving particles that have a positive charge. He asked one of his students to find out what happens to the alpha particles when they passs through a thin sheet of gold. This helped Ruthford with his model.

Ernest Marsden

Oct 31, 1911

Marsden studied the path of an alpha particle. He aimed an arrow beam of alpha particles at the gold plate to figure his investigation out.

Niel Bohr

Oct 29, 1913

Bohr studied how electrons move with constant speed and orbits around the nucleous. He discovered energy levels. He worked with ruthford and studied ruthfords model to create his own. Bohr's only focused on electrons.

Louis de Brogile

Oct 29, 1924

Louis de Brogile proposes that moving particles like electrons have some properties similar to waves. He used other peoples work such as Max Planck, Albert Einstein (wave particles on light waves), and David Bohm (matter waves) to come up with his own model.

Erwin Schrodinger

Oct 29, 1926

Schrodinger developed math equations to describe the motion of electrons in atoms. He used the Cloud model. He collected evidence from Louis Victor de Broglie 's work regarding atomic matter. He searched for ways to make Bohr's model better. Schrodinger used Bohr's model to come up with his own model.

James Chadwick

Oct 29, 1932

Chadwick confirmed that the existence of neutrons have no charge. James Chadwick studied atomic decay. Chadwick repeated Frederic and Curies experiments with the goal of looking for a neutron particle; one with the same mass as a proton but with no charge.

Gustav Hertz

Jun 11, 1945

Hertz thought that when electrons strike the atom of mercury vapour the electrons must come to a certain energy.He carried out experiments where they destroyed mercury atoms with electrons.