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The Alchemists contributed to the atom by breaking down the chemical compositions of fire, wind, earth, and water which eventually evolved into the Periodic Table of Elements. (500 BCE) -
Plato contributed to the atom when he was convinced that atoms of matter must derive from 5 fundamental solids. (427 BCE) -
Democritus contributed to the atom when he theorized that all material bodies were made up of indivisibly small "atoms". (400 BCE) -
Robert Boyle contributed to the atom when he helped develop the definition of an element. (1661) -
Antone Lavoisier contributed to the atom when he discovered that the total mass of products and reactants in a chemical reaction is always the same (conservation of mass) which meant that the same number and kind of atom is present before and after a chemical change. (1772) -
The Billiard Ball Model was created in 1803 by John Dalton
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John Dalton contributed to the atom when his atomic theory was the first complete attempt to describe all matter in terms of atoms and their properties. (1808) -
Amedeo Avogadro contributed to the atom when he discovered that hydrogen, nitrogen, and oxygen were composed of 2 atoms. (1811) -
Dimitri Mendeleev contributed to the atom when he devised the periodic classification of the chemical elements, in which the elements are arranged in order of increasing atomic weight. (1869) -
The Plum Pudding Model was created in 1897 by JJ Thompson -
JJ Thompson contributed to the atom when he proved that all atoms contained tiny negatively charged subatomic particles or electrons.(1897) -
Pierre and Marie Curie contributed to the atom when they discovered ionizing, which was penetrating rays created by certain atoms. (1898) -
Albert Einstein contributed to the atom when he mathematically proved the existence of atoms which revolutionized all the sciences. (1905) -
Robert Millikan contributed to the atom when he determined the magnitude of the electron's charge. (1910) -
Ernest Rutherford contributed to the atom by discovering that the atom consisted of mostly empty space, with its mass concentrated in a central positive nucleus. (1911) -
The Solar System Model was created in 1913 by Ernest Rutherford -
Neils Bohr contributed to the atom when he proposed a theory for the hydrogen atom and realized that electrons did not crash into the nucleus. (1913) -
Henry G. J. Mosely contributed to the atom when he proved that every element's identity is uniquely determined by the number of protons it has. (1913) -
The Electron Cloud Model was created in 1926 by Erwin Schrodinger -
Erwin Schrodinger contributed to the atom when he described the likelihood of finding an electron in a certain position. (1926) -
Werner Hisenberg contributed to the atom when he discovered that a particles position and momentum could not be known exactly. (1927) -
James Chadwick contributed to the atom when he discovered neutrons in atoms. (1932)
