The History of Atomic Theoretical Creations

Aristotle

200

Aristotle believed that substances were built up from four elements; Air, Earth, Water, and Fire. These elements were a combination of qualities: wet, cold, dry, and hot. he, too, used reason to come up with this theory.

Isaac Newton

Feb 6, 1643

Isaac believed all atoms are held together by attractions.

John Dalton

Oct 31, 1803

John believed that atoms were small particles that were indestructible and had no internal structure. John got evidence by measuring the mass of elements that combine when compounds are formed.

J.J Thomson

Oct 31, 1897

Thomson suggested that elctrons are imbedded in a sphere of positive electric charges.
He constructed a different cathode ray tube, with a fluorescent coating at one end and a "near perfect" vacuum. in the middle of the tube were two electric plates, producing a positive anode and a negative cathode, which he hoped for. would deflect the rays in which it did.

Hantaro Nagaoka

Oct 31, 1904

Nagaoka thought that an atom has a central nucleus which brings the electrons to move in orbits like the rings around Saturn. Hantaro could not prove his theory on his own.

Ernest Marsden

Oct 31, 1909

Ernest Marsden worked with Retherford. They created the Gold Foil Experiment to prove rutherfords theory.

Ernest Rutherford

Oct 31, 1911

Ernest stated thatan atom has a dense, positively charged nucleus sothe electrons move at random around the nucleus. He and Marsden used the Gold Foil experiment and this was what helped them find the nucleus.

Niels Bohr

Oct 31, 1913

Bohr's atomic model proposed that electrons move in spherical orbits at fixed distances away from the nucleus. He, too worked with Rutherford to get his information.

Louis de Brogile

Oct 31, 1924

Louis contributed the thought that moving particles like electrons have some properties of waves. This work was developed with the help of Max Planck.

Erwin Schrodinger

Oct 31, 1926

He believed electrons behaved like waves of energy. In his model, electrons are viewed as continuous clouds. He made up math equations to get this theory.

James Chadwick

Oct 31, 1932

He discovered the neutrons which is the nucleus with protons.

Heisenberg, Werner

Oct 5, 1989

He pointed out that it is impossible to know both the exact position and the exact momentum of an object at the same time. He knows this because while measuring one aspect, you alter others, you cannot know every principle.

Democritus

Oct 31, 2001

Democritus said that all matter consisted of extremely small particles that cannot be separated he also thought that there were different types of atoms. This theory was based on reasoning. He knew that if you were cutting a stone in halves, the stone had the same particles but would become "indevisible".