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415 BCE
Democritus
4th-5th Century B.C.E
This is the man who originated with the idea that a smallest particle exists. This particle was named atomos and was the foundation of atomic theory. -
310 BCE
Aristotle
4th Century B.C.E
A greek philosopher with the idea that by cutting a piece of matter by half each time, the result would be a smaller piece. He mainly disagreed with Democritus on his entire theory. -
Isaac Newton
1704 A.D.
Proposed the idea of a universe that was mechanical which had small solid masses in motion. Also an idea that particles are attracted to each other by forces. -
John Dalton
1803 A.D.
The individual who proposed the atomic theory. This included considering spherical solid atoms based upon measurable properties of mass -
Ludwig Boltzmann
1871 A.D.
A scientist who developed statistical mathematics. Also showed how the properties of atoms affect the properties of matter. -
J.J. Thomson
1897 A.D.
Using a cathode ray tube, he identified the negatively charged electron. Believed that the electron was a part of all matter. -
Ernest Rutherford
1911 A.D.
Conducted a gold foil experiment to discover the nuclear atom. This meant that atoms had a positive charged center which was surrounded by negative particles. -
Neils Bohr
1913 A.D.
Refined Rutherford’s model by explaining that electrons orbit the nucleus without losing energy and at different levels of energy moved in fixed orbits. -
Erwin Schrödinger
1926 A.D.
Found wave functions for electrons. Believed electrons in orbit would set up waves and could identify the probability of where an electron might be. -
James Chadwick
1932 A.D.
In collaboration with Rutherford was able to discover the neutron. This lead to the discovery of fission.
