History of Chemistry

By leiziel
  • 1770 BCE

    King Hammurabi's reign over Babylon

    Known metals were recorded and listed in conjunction with heavenly bodies.
  • 430 BCE

    Democritus of ancient Greece

    Democritus proclaims the atom to be the simplest unit of matter. All matter was composed of atoms.
  • 300 BCE

    Aristotle of ancient Greece

    Aristotle declares the existence of only four elements: fire, air, water and earth. All matter is made up of these four elements and matter had four properties: hot, cold, dry and wet.
  • 300

    The Advent of the Alchemists

    Influenced greatly by Aristotle's ideas, alchemists attempted to transmute cheap metals to gold. The substance used for this conversion was called the "Philosopher's Stone".
  • 1200

    Failure of the Gold Business

    Although Pope John XXII issued an edict against gold-making, the gold business continued. Despite the alchemists' efforts, transmutation of cheap metals to gold never happened within this time period.
  • 1520

    Elixir of Life

    Alchemists not only wanted to convert metals to gold, but they also wanted to find a chemical concoction that would enable people to live longer and cure all ailments. This elixir of life never happened either.

  • Death of Alchemy

    The disproving of Aristotle's four-elements theory and the publishing of the book, The Skeptical Chemist (by Robert Boyle), combined to destroy this early form of chemistry.

  • Phlogiston Theory

    Johann J. Beecher believed in a substance called phlogiston. When a substance is burned, phlogiston was supposedly added from the air to the flame of the burning object. In some substances, a product is produced. For example, calx of mercury plus phlogiston gives the product of mercury.

  • Coulomb's Law

    Charles Coulomb discovered that given two particles separated by a certain distance, the force of attraction or repulsion is directly proportional to the product of the two charges and is inversely proportional to the distance between the two charges.

  • Disproving of the Phlogiston Theory

    Joseph Priestley heated calx of mercury, collected the colorless gas and burned different substances in this colorless gas. Priestley called the gas "dephlogisticated air", but it was actually oxygen. It was Antoine Lavoisier who disproved the Phlogiston Theory. He renamed the "dephlogisticated air" oxygen when he realized that the oxygen was the part of air that combines with substances as they burn. Because of Lavoisier's work, Lavoisier is now called the "Father of Modern Chemistry".

  • Dalton's Atomic Theory

    John Dalton publishes his Atomic Theory which states that all matter is composed of atoms, which are small and indivisible.

  • Vacuum Tube

    Heinrich Geissler creates the first vacuum tube.

  • Cathode Rays

    William Crookes made headway in modern atomic theory when he used the vacuum tube made by Heinrich Geissler to discover cathode rays. Crookes created a glass vacuum tube which had a zinc sulfide coating on the inside of one end, a metal cathode imbedded in the other end and a metal anode in the shape of a cross in the middle of the tube. When electricity was run through the apparatus, an image of the cross appeared and the zinc sulfide glowed.

  • The Proton

    Eugene Goldstein discovered positive particles by using a tube filled with hydrogen gas (this tube was similar to Thomson's tube...see 1897). The positive particle had a charge equal and opposite to the electron. It also had a mass of 1.66E-24 grams or one atomic mass unit. The positive particle was named the proton.

  • X-rays

    Wilhelm Roentgen accidentally discovered x-rays while researching the glow produced by cathode rays. Roentgen performed his research on cathode rays within a dark room and during his research, he noticed that a bottle of barium platinocyanide was glowing on a shelf. He discovered that the rays that were causing the fluorescence could also pass through glass, cardboard and walls. The rays were called x-rays.

  • Pitchblend

    Henri Becquerel was studying the fluorescence of pitchblend when he discovered a property of the pitchblend compound. Pitchblend gave a fluorescent light with or without the aid of sunlight.

  • The Electron and Its Properties

    J.J. Thomson placed the Crookes' tube within a magnetic field. He found that the cathode rays were negatively charged and that each charge had a mass ratio of 1.759E8 coulombs per gram. He concluded that all atoms have this negative charge (through more experiments) and he renamed the cathode rays electrons. His model of the atom showed a sphere of positively charged material with negative electrons stuck in it. Thomson received the 1906 Nobel Prize in physics.

  • Radioactive elements

    Marie Curie discovered uranium and thorium within pitchblend. She then continued to discover two previously unknown elements: radium and polonium. These two new elements were also found in pitchblend. She received two nobel prizes for her discovery; one was in chemistry while the other was in physics.

  • Mass of the Electron

    Robert Millikan discovered the mass of an electron by introducing charged oil droplets into an electrically charged field. The charge of the electron was found to be 1.602E-19 coulombs. Using Thomson's mass ration, Millikan found the mass of one electron to be 9.11E-28 grams. Millikan received the 1932 Nobel Prize in Physics for this discovery.

  • The Three Types of Radioactivity

    Ernest Rutherford sent a radioactive source through a magnetic field. Some of the radioactivity was deflected to the positive plate; some of it was deflected to the negative plate; and the rest went through the magnetic field without deflection. Thus, there were three types of radioactivity: alpha particles (+), beta particles (-) and gamma rays (neutral). By performing other experiments and using this information, Rutherford created an atomic model different from Thomson's.

  • Protons within a Nucleus

    Henry Moseley attempts to use x-rays to determine the number of protons in the nucleus of each atom. He was unsuccessful because the neutron had not been discovered yet.

  • The Neutron

    James Chadwick discovers the neutron.

  • Neutron Bombardment and Nuclear Fission

    Enrico Fermi bombards elements with neutrons and produces elements of the next highest atomic number. Nuclear fission occurred when Fermi bombarded uranium with neutrons. He received the 1938 Nobel Prize in physics.

  • Artificial radioactive elements

    Irene Curie and Frederic Joliot-Curie discovered that radioactive elements could be created artificially in the lab with the bombardment of alpha particles on certain elements. They were given the 1935 Nobel Prize.

  • Manhattan Project

    Albert Einstein and Enrico Fermi both warned the United States about Germany's extensive research on atomic fission reaction. Below the football field at the University of Chicago, the United States developed the very first working nuclear fission reactor. The Manhattan Project was in process.