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400 BCE
Empedocles
Empedocles put forward an idea that all matter was divided into 4 different elements. Which were air, fire, water, and earth. After he suggested his theory, it was accepted by Aristotle. Aristotle was one of the most famous greek philosophers. -
370 BCE
Democritus
Democritus discovered that everything around us was created by atoms that are indestructible, always in motion and between atoms is empty space. -
150 BCE
Asharya kanad
Asharya Kanad is believed to be the one to theorize the idea of a particle of the matter being indestructible and indivisible. The way he thought of this, was by cutting fruit into smaller and smaller pieces/ -
1500
The Alchemists
The Alchemists were an ancient form of chemistry, which branched off of greek and roman philosophy. Their mission was to turn regular metals into gold. They were as well looking for the philosophers stone which was said to bring perfection to life. Through many of these tests, they founded many elements still on the periodic table today. -
John Dalton
John Dalton created a theory that stated that all matter is composed of atoms that are extremely small and indivisible. He said that atoms within a certain element were all the same, however, within different atoms the sizes and mass differ. -
Marie Sklodowska Curie
Marie Sklodowska Curie she conducted an experiment, in which she tested Uranium rays. In conclusion of the experiment, she theorized that the waves were based on the atomic structure of the element. -
Max Planck
Max Planck was a German scientist, he is known for originating the quantum theory. The theory bettered our understanding of atomic and subatomic processes. -
J.J Thomson
J.J Thomson is known for discovering that all atoms have negatively charged subatomic particles called electrons. He then went on to create an atomic model called the plum pudding model. -
Hantaro Nagaoka
Hantaro Nagaoka was a Japanese scientist, who purposed in 1904 an alternative planetary model of the atom. His idea was that electrons orbit a center that's positively charged. He based this off of the planet Saturn (rings). -
Ernest Rutherford
Ernest Rutherford proposed that an atom is mostly space and has electrons orbiting in space, in a predictable set path around a positively charged nucleus. -
Neils Bohr
Neils Bohr is known for his theory that electrons surround and revolve the center of an atom. He also discovered that when an electron transfer from one orbit to another with a lower energy a quantum light is released. -
Louis De Borglie
Louis De Borglie had an idea that all matter and electrons have wave properties. This idea is the theory called De Borglie hypothesis and is the main core of quantum mechanics. -
Wolfgang Pauli
Wolfgang Pauli was an Austrian scientist, who won the Nobel prize in 1945. He won it for his discovery of the Pauli exclusion principle. The principle states that no two electrons in an atom can be at the same time in the same state or configuration. -
Werner Heisenberg
Werner Heisenberg, discovered when he was only 23 a theory that he has won a Nobel prize for in 1932. The theory was that we cannot assign to an electron a position in space at any given time, or follow it in its orbital. What Heisenberg noticed was that we couldn't assume that Bohr's digram (Planetary orbits) actually exists. -
Erwin Schrodinger
Erwin Schrodinger was an Austrian scientist. He took the Bohr model one step further by using math equations to describe the likelihood of finding an electron in a certain position. His model is known as the quantum mechanical model. -
James Chadwick
James Chadwick was a British scientists and in 1932, made one of the largest discoveries in science. He discovered neutrons. In doing so he won a Nobel prize in 1935. -
Lise Meitner
Lise Meitner was a Swedish scientist who discovered that nuclear fission can produce large amounts of energy. She was claimed as the mother of the atomic bomb. -
Albert Einstein
Albert Einstein is most known for his theory of relativity E=MC^2, but his largest contribution to atomic theory is his work with the atomic bomb. -
Rosalind Franklin
Rosalind Franklin was a British scientist who contributed to science. She discovered the molecular structure of coal and carbon, were used to create strong carbon fibers and slow reactions in nuclear power plants. -
Robert J. Le Roy
Robert J. Le Roy, for the most part, studied with forces within molecules. He utilized quantum mechanics and computer models to depict the forces between atoms. -
Ronald J. Gillespie
Ronald J. Gillespie was a chemistry professor at the University of McMaster. Mr. Gillespie contributed to science by creating superacid, which became widely used in organic and inorganic chemistry. He also developed with the aid of R. S. Nyholm developed the widely used valance shell electron pair repulsion theory. -
Richard Bader
Richard Bader discovered that the electron density is a very important factor when explaining the behavior of atoms. He also theorized that atoms do not actually have orbitals.
