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1700s
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. -
Period: to
History of Chemistry
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1803
Dalton's Atomic Theory: John Dalton publishes his Atomic Theory which states that all matter is composed of atoms, which are small and indivisible. -
1885
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. -
1911
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 Th -
1940s
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.
