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427 BCE
Plato
Plato was known as a classical Athenian philosopher in ancient Greece. Plato introduced atomic theory where ideal geometric forms serve as atoms. He concluded that atoms mathematically broke down into triangles and different elements had different shapes. Fire (tetrahedron), air (octahedron), water (icosahedron), earth (cube), -
400 BCE
Democritus
Democritus was a central figure in the development of the atomic theory of the universe. Democritus was the first to theorize that all things were made of incredibly small individual particles. That is now known as atoms. Democritus was one of the two founders of the ancient atomist theory. -
350 BCE
Aristotle
Aristotle had layed the foundation for things such as elements, pure substances, and chemical combination. Aristotle founded the idea that all pure substances were homoamorous and were made up of the elements such as air, earth, fire, and water. -
Lavoisier
Antoine Lavoisier was a French chemist with the nickname "father of modern chemistry." Antoine Lavoisier established the law of conservation of mass, Antoine Lavoisier discovered that combustion and respiration are caused by chemical reactions with Oxygen. He was also the one who names oxygen. Antoine Lavoisier systematized chemical nomenclature. -
John Dalton
John Dalton was an English chemist, physicist, and meteorologist who introduced atomic numbers into chemistry. John Dalton did an experiment where he combined oxygen with either one or two volumes of nitric oxide in closed vessels over water farther proving his evidence for atomic numbers. -
Newland's law of Octaves
Founded by chemist J.A.R. Newlands. Newlands major discovery was elements were arranged to their increasing atomic weight. Elements that have similar physical or similar chemical properties have a pattern that shows after intervals of 7. -
Mendeleev’s Pd. Table
Founded by Russian chemist Dmitri Mendeleev, Mendeleev’s Pd. Table was the first ever one. He was the one who invented the periodic table. Dmitri Mendeleev came up with all the symbols of the chemicals and put them in order according to their atomic number. Dmitri Mendeleev wrote them down in groups of similar behavior which was a breakthrough for chemistry. -
Photoelectric Effect
Founded by physicist Heinrich Rudolf Hertz by shining an ultra volant light on electrodes causing a change in the voltage between them. -
Discovery of Radioactivity
Radioactivity was first accidentally founded by Henri Becquerel when he opened up his drawer and discovered spontaneous radioactivity. -
Discovery of the electron
The electron was discovered by Joseph John Thomson by In his experiments, he used cathode rays in which he bent over to one side and which electricity flowed through, so he knew there must be some small particle in which electricity may flow through. -
Planck’s Quantum Theory of Light
Discovered by Niels Bohr and Max Planck, Planck’s Quantum Theory of Light has twi things.
1.) Different atoms and molecules can emit or absorb energy in discrete quantities only. The smallest amount of energy that can be emitted or absorbed in the form of electromagnetic radiation is known as quantum. 2.)The energy of the radiation absorbed or emitted is directly proportional to the frequency of the radiation. Albert Einstein used his properties to describe the particle properties of light. -
Plum Pudding Model
Plum Pudding Model was founded by J.J. Thomson. Plum pudding is an English dessert similar to a blueberry muffin. In Thomson's plum pudding model of the atom, the electrons were in an area of positive charge, like blueberries stuck into a muffin. The positive matter was thought to be jelly-like,. The electrons could move just a little bit. The closer to the outer portion of the atom, the higher the positive charge was because of that the electron would be pulled towards the middle. 1903 -
Robert Millikan
Robert Andrews Millikan was an American physicist who discovered the elementary charge of an electron using the oil-drop experiment. The elementary charge was the magnitude carried by a single electron. -
Charge of the Electron
Robert Millikan founded the charge of the electron. He discovered it in his oil drop experiment. The electron carries a charge of 1.602176634 × 10−19 coulomb. -
Rutherford’s Gold Foil Experiment
Founded by Physicist Ernest Rutherford, the Rutherford’s Gold Foil Experiment was an experiment in which alpha particles were shot onto a thin piece of gold foil. The alpha particles passed through the phosphorescent screen encasing the foil. This caused a huge flash of light. -
Bohr’s Planetary Model
The Bohr Model was founded by physicist Niels Bohr and is a structural model of an atom that is similar to a planetary model where electrons orbit in specific paths around a nucleus. -
Mosely's Atomic Numbers
Henry Moseley figured out that the atomic number in an atom is the amount of protons. He discovered 3 unknown elements with the atomic numbers 43, 61 and 75 between aluminum and gold on the periodic table. -
Discovery of the proton
The proton was founded by Ernest Rutherford when his research resulted in a nuclear reaction which was the first splitting of an atom. -
Schrodinger Equation
The Schrodinger Equation uses the concept of energy conservation (Kinetic Energy + Potential Energy = Total Energy) so it can obtain information about the behavior of a electron bound nucleus . HΨ = EΨ -
Heisenberg Uncertainty Principle
Founded by Werner Heisenberg the Heisenberg Uncertainty Principle is the unknowingness of a particle. You can not get an accuracy on both a particles position and speed. The more you pinpoint the speed of a particle the less accurate the position of the particle is. -
Discovery of the Neutron
The neutron was discovered by James Chadwick by a experiment conducted which he filled Beryllium with alpha particles from the natural radioactive decay of Polonium. this experiment resulted in radiation showing high penetration through a lead shield. At the time, the results could not be explained with any of the known particles, leading to the discovery of the neutron. -
The Alchemists
The Alchemists developed practical knowledge about matter as well as sophisticated theories about its hidden nature and transformations. Their goal was to discover the secret of preparing the philosophers stone. The stone could transmute base metals into gold.