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Antoine Lavoisier
Antoine Lavoisier was a french chemist who discovered many advancements about modern chemistry, but his most important one was his discovery about the importance of oxygen. He discredited the now obselete phlogiston theory with his own theory on oxygen combustion. He also recognized oxygen as the principle element in the atmosphere, interpreted its role in plant and animal respiration, figured out how oxidation involves oxygen being consumed and energy being released, and gave it its name. -
Antoine-Laurent Lavoisier
"The father of modern chemistry". Lavoisier proved that combustion is when a substance burns and joins with the element oxygen, and that the mass of the reactants is equal to the mass of the products in a reaction. He also defined an element as a substance that cannot be broken down any further.
Scratch, Lydia S. "Antoine Lavoisier." Chemistry Explained, n.d. Advameg Inc., 2014. Web. 13 Mar 2014.
"Antoine Lavoisier." Purdue, n.d. Purdue University, 2004. Web. 8 Mar 2014. -
John Dalton Proposed his Atomic Theory
"John Dalton Biography." Bio.com. A&E Networks Television, n.d. Web. 9 Mar. 2014. John Dalton was an English meteorologist and chemist. In 1803 he proposed his atomic theory which was a conclusion drawn from his research into gasses, in which he discovered that certain gasses could only be combined in certain proportions even if two different compounds shared the same common element or group of elements. -
Amedeo Avogadro
In 1811, Avogadro stated that equal amounts of volumes of gases at the same temperature and pressure, (STP), contain the same number of molecules. Although he strongly believed in this hypothesis, at the time of his discovery, the concept of atomic weights faced confusion. Avogadro’s hypothesis only gained popularity two years after his death. Avogadro's discovery led to many important advancement in atomic theory, for example; Avogadro's Constant. -
Amadeo Avogadro
In 1811, Avogadro hypothesized that at equal temperatures and pressures, equal volumes of gases will contain the same number of molecules. This hypothesis led to the idea that the ratio of molecular mass to density between any two gases under the same conditions would be the same. From this discovery, Avogadro's law was created. This law was a great advancement in atomic theory because it meant that the relative molecular mass of a sample of known volume. -
Medeleev - First Discovery of the Periodic Table
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Becquerel
Becquerel discovers that Uranium emits radiation not x-rays. -
J.J. Thomson
In 1987, J.J. Thomson discovered part of the subatomic structure of the atom, as well as proving the existence of the electron, the negatively charged subatomic particle. As well as this, he recognized the ratio of charge to mass of the electron in an atom. Citation: JJ (Joseph John) Thomson (1856-1940) British Physicist: Discoverer Of Electron And Pioneer Of Nuclear Physics. From Photograph Taken Pre-1916.. Photography. Encyclopædia Britannica ImageQuest. Web. 12 Mar 2014. http://quest.eb.com/i -
JJ Thomson - Discovery of Electrons and Isotopes
JJ Thomson was a repected professor at Trinity College in Cambridge, Britain. Students from across the world came to listen to his classes. One of his students was Ernest Rutherford. In 1897, Thomson researched the electric discharge of a cathode ray tube. He discovered the existence of electrons and the ratio of an electron's charge to mass. In 1906, he was awarded the Nobel Prize of Physics. In 1906, Thomson discovered mass spectrometry. This led to him proving the existence of isotopes. -
Marie Curie
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Max Planck
On December 14th 1900, Max Planck published his "Quantum Hypothesis." to the German Physical Society He stated that energy existed in "quanta" or discrete packets, instead of a continuous electromagnetic wave. This concept, embodied by Plancks constant (h =6.626 x 10-34Js) in his equation v: E=hv. -
Heisenberg
Heisenberg has been commended for his theory of quantum mechanics, Principle of Uncertainty and Triumph of the Copenhagen Interpretation. -
Hantaro Nagaoka
Hantaro Nagaoka (August 15, 1865 – December 11, 1950) was a Japanese physicist who developed the Saturnian atomic model, which was published in 1904. The model consisted of a massive, positively-charged sphere, encircled by flat rings of negatively-charged electrons bound by electrostatic forces. Nagaoka was the first person to defend a planetary model of the atom, which turned out to be more accurate than Thomson's plum pudding model. -
Einstein published his theory on motion of Atoms
(THIS WAS PUBLISHED IN THE EARLY 1900'S)
He published in the Brownian Movement that stated
statistical physics in “On the Motion of Small Particles Suspended in a Stationary Liquid, as required by the Molecular Kinetic Theory Of Heat”. -
Einstein prooves the existence of atoms with Math
In his "miracle year" Einstein published a paper titiled "On the Movement of Small Particles Suspended in Stationary Liquids Required by the Molecular-Kinetic theory of Heat." By studying the seemingly random motion of particles in fluid, Einstein used mathematical equations to calculate the size of atoms. He proved atoms of a definite size existed, even if they were invisible to the human eye.- Kristina Luu
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Marie Curie's Work on Radioactivity is Published
The date is not exact but during this year, all the work that Marie Curie had done with her husband Pierre was published. She and her husband had discovered two new elements, polonium (named after Poland) and radium in a mineral called "pitchblende". Furthermore, Curie also noted that thorium had similar properties to uranium. -
Ernest Rutherford - The Gold Foil Experiment
His gold foil experiment disproved the “plum pudding” model, and gave new data which described the atom as having a dense, positively charged core called a nucleus, where mostly all the mass is concentrated.
He also discovered that there are electrons that circulate around the nucleus. This was contradictory to the “plum pudding” model, which suggested that electrons were inside a ball of protons.
While his experiment affirmed that the atom’s nucleus was composed of positively charged particl -
Neils Bohr Atomic Therory
Niels Bohr discovered new information about the atoms in particles and how they relate to each other. He added on to Rutherford’s theory: atoms contain a positive nucleus and orbiting negative electrons, by proposing that the electrons orbit around the nucleus in specific shells. He did so by creating the Bohr's model, a model that illustrated the number of electrons that orbit around the nucleus. Bohr introduced his Bohr mod Bohr, Niels. Photograph. Encyclopædia Britannica. Web. 12 Mar. 2014. -
Niels Bohr: Atomic Model
Biography: Niels Bohr was a Danish physicist who is a significant physicist of the 20th century. He was the very first scientist to apply the quantum theory to atomic and molecular structure. In 1903 Bohr was enrolled at the University of Copenhagen where he studied physics. He researched and taught at the Polytechnic Institute. In 1911 he obtained his doctorate with a dissertation on the electron theory of metals. -
Werner Karl Heisenberg's Uncertainty Principle
Heisenberg created his principle of uncertainty. He discovered that it is impossible to know, with full certainty, both the momentum and the exact position of an electron. He also discovered that the more you know about one of these two variables, the harder it is to measure the other one. If one cannot measure the momentum and position of electrons, there is no way to prove that they are lined up in orbits (which was the case according to Bohr’s model) --> leading to the Quantum Atomic Model -
James Chadwick proves the existence of the neutron.
James Chadwick is an English physicist. He proved the existence of the neutron in 1932. Chadwick noticed that something was really weird because the atomic number (# of protons in the nucleus) was less than the atomic mass (average mass of the atom). He speculated that something else, other than protons, was present in the nucleus. Portrait Of Sir James Chadwick, Physicist. Photography.Encyclopædia Britannica ImageQuest. Web. 9 Mar 2014 -
Erwin Schrodigner
Ewrin Schrodigner's paradoxical quantum theory of superpotition was performed in 1935.ramer, Melody Krame. "The Physics Behind Schrödinger's Cat Paradox." National Geographic . N.p., 12 Aug. ramer, Melody Krame. "The Physics Behind Schrödinger's Cat Paradox." National Geographic . N.p., 12 Aug.ramer, Melody Krame. "The Physics Behind Schrödinger's Cat Paradox." National Geographic . N.p., 12 Aug. -
JJ Thomson Discovered the Electron
