Chemistry History

By Caitlynnhi23
  • 460 BCE

    Democritus

    Democritus
    Atomos: that which cannot be cut.
    B. Definition of Atom: the smallest unit of matter which still retains the
    identity and properties of that matter.
  • 384 BCE

    Aristotle

    Aristotle
     Refuted Democritus
     Believed in four elements: Earth, Air, Fire, and Water.
     Aristotle’s refutation of Democritus’ Atomic Theory led to nearly
    2000 years of bogus “science” Among the most prominent:
  • 300

    Alchemy

    Alchemy
     332 BC Alexander the Great had conquered Egypt
     Greek philosophers became interested in the Egyptian religion. Greek
    views of how matter is made up of the four elements of nature were
    merged with Egyptian religion.
     The result was Khemia, the Greek word for Egypt.
     The word Alchemy came from the word Khemia, which means Egypt.
     @600 A.D. Arabs occupied Egypt and further developed the science,
    spread it to the West (Spain) in 700s.

  • The Phlogiston Theory

    The Phlogiston Theory
    from the Ancient Greek phlogistón "burning up"
     first stated in 1667 by Johann Joachim Becher
     postulated the existence of a fire-like element called "phlogiston",
    which was contained within combustible bodies and released
    during combustion.
     A substance that burned did so because it contained Phlogiston.
     Carbon Dioxide, no longer capable of burning was called
    “dephlogisticated air”
  • Period: to

    Anton Laurent de La Voisier : Father of Modern Chemistry

    Father of Modern Chemistry because he relied on quantitative
    observation to develop conclusions.
     Dispelled the Phlogiston Theory by proving that Oxygen causes
    combustion.
     Discovered the Law of Conservation of Mass: By proving that the
    mass of a metal oxide = the mass of the metal plus oxygen when
    the metal oxide decomposes.
     Matter can change form, but cannot be created nor destroyed
    in a chemical reaction.
     Beheaded during French Revolution

  • Benjamin Franklin

    Benjamin Franklin
    Discovered that electrical charges come in 2 varieties – positive and
    negative. Like charges repel, opposite charges attract.

  • Joseph Louis Proust

    Joseph Louis Proust
    The Law of Definite Proportions, sometimes called The Law of
    Constant Composition, states that a chemical compound always
    contains exactly the same proportion of elements by mass.

  • John Dalton

    John Dalton
    Dalton’s Atomic Theory of Matter:
    A. Matter is made up of atoms that are indivisible and indestructible.
    B. All atoms of an element are identical. (Known now to be untrue!)
    C. Atoms of different elements have different weights and different
    chemical properties.
    D. Atoms of different elements combine in simple whole numbers to
    form compounds.
    E. Atoms cannot be created or destroyed. When a compound
    decomposes, the atoms are recovered unchanged.3

  • William Crookes et.al.

    William Crookes et.al.
    He discovered the element thallium and worked on his cathode-ray studies

  • Sir John Joseph Thomson

    Sir John Joseph Thomson
    He continued experimenting on the CRT.
    JJ Thomson used charged plates to deflect the cathode ray. Found the ray deflected away from the negative plate, and toward the positive.

  • Ernest Rutherford

    Ernest Rutherford
    He classified radiation

  • Becquerel

    Becquerel
    He discovered radioactivity in Uranium ore.

  • Curies (Marie and Pierre)

    Curies (Marie and Pierre)
    They discovered and isolated polonium and radium from uranium ores.

  • Millikan

    Millikan
    He calculated the mass and charge of an electron.

  • James Chadwick

    James Chadwick
    He provided that neutrons had no charge.