SCIENTISTS Flashcards
(17 cards)
both warned the United States about Germany’s extensive research on atomic fission reaction. University of Chicago, of United State developed the very first working nuclear fission reactor. The Manhattan Project was in process.
Albert Einstein and Enrico Fermi
discovered that radioactive elements could be created artificially in the lab with the bombardment of alpha particles on certain elements. They were give the 1935 Nobel Prize.
Irene Curie and Frederic Joliot-Curie
discovers the neutron.
Nuclear fission occurred when Fermi bombarded uranium with neutrons. He received the 1938 Nobel Prize in Physics.
James Chadwick
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.
Henry Moseley
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 particle (+), beta particles (-) and gamma rays (neutral). By performing other experiments and using this information, created an atomic model different from Thomson’s. he believed that the atom was mostly empty space. It contains an extremely tiny, dense positively charged nucleus (full of protons) and the nucleus is surrounded by electrons traveling at extremely high speeds..
Ernest Rutherford
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 ratio, found the mass of one electron to be 9.11E-28 grams. he received the 1932 Nobel Prize in Physics for his discovery.
Robert Millikan
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.
Marie Curie
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. received the 1996 Nobel Prize in physics.
J.J. Thomson
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
Henri Becquerel
accidentally discovered x-rays while researching the glow produced by cathode rays. 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.
Wilhelm Roentgen
discovered positive particles by using a tube filled with hydrogen gas. 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.
Eugene Goldstein
made headway in modern atomic theory when he used the vacuum tube made by Heinrich Geissler to discover cathode rays. 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. hypothesized that there must have been rays coming from the cathode which caused the zinc sulfide to fluoresce and the cross to create a shadow and these rays were called cathode rays.
William Crookes
Heinrich Geissler
creates the first vacuum tube.
publishes his Atomic Theory which states that all matter is composed of atoms, which are small and indivisible.
John Dalton
heated calx (metal oxide) of mercury, collected the colorless gas and burned different substances in this colorless gas. called the gas “dephlogisticated air,” but it was actually oxygen
Joseph Priestley
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.
Johann J. Beecher
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.
Charles Coulomb
