History of the Atom

  • Period: 500 BCE to

    History of the Atom

  • Democritus
    400 BCE

    Democritus

    Theorized some properties of atoms. He also theorized that atoms were specific to the material they composed. Source: American Board
  • The Alchemists
    100 BCE

    The Alchemists

    Their studies of the scientific process and natural processes allowed us to later discover the atom. Source: Health Research Funding
  • Plato
    438

    Plato

    Came up with a theory that stated that ideal geometric shapes form atoms. Source: Sutori
  • Robert Boyle

    Robert Boyle

    Demonstrated that matter is made of tiny particles. He called them corpuscles. Source: Study.com
  • Antoine Lavoisier

    Antoine Lavoisier

    Defined elements as chemicals that could not be broken down. Source: Study.com
  • Billiard Ball Model

    Billiard Ball Model

    A model by John Dalton that showed the atom as a ball like structure. Source: Brilliant
  • John Dalton

    John Dalton

    Published a theory on atomic theory. He suggested that all matter is made of atoms with distinct properties (elements). Source: Royal Society
  • Amedeo Avogadro

    Amedeo Avogadro

    Stated that equal volumes of gases at the same temperature contained the same number of molecules. He also stated that elementary gases are composed of two atoms. Source: Le Monye College
  • Dmitri Mendeleev

    Dmitri Mendeleev

    Devised the periodic table. Source: Britannica
  • J.J. Thomson

    J.J. Thomson

    Came up with an experiment that proved the existence of electrons. Source: Khan Academy
  • Pierre and Marie Curie

    Pierre and Marie Curie

    Discovered and coined the term radioactivity by discovering radium and polodium. Source: Britannica
  • Plum Pudding Model

    Plum Pudding Model

    A model by J.J. Thomson that had electrons embedded in a positively-charged soup. Source: Khan Academy
  • Albert Einstein

    Albert Einstein

    Mathematically predicted the size of atoms and proved their existence. Source: Ck12
  • Robert Millikan

    Robert Millikan

    Discovered the charge of electrons. Source: Nobel Prize
  • Ernest Rutherford

    Ernest Rutherford

    Established that the mass of an atom is concentrated in its nucleus. Source: Primary Connections
  • Neils Bohr

    Neils Bohr

    Proposed a theory on the hydrogen atom and another on radiation. Source: Nobel Prize
  • Henry G. J. Mosely

    Henry G. J. Mosely

    Arranged the elements of the periodic table by atomic number and proved that the atomic number is the number of positive charges in the atomic nucleus. Source: Britannica
  • Solar System Model

    Solar System Model

    A model by Neils Borh that showed that electrons orbit the nucleus. Source: American Board
  • Electron Cloud Model

    Electron Cloud Model

    A model used to estimate the location of electrons. It was developed by Erwin Schrödinger and Werner Heisenberg. Source: Study.com
  • James Chadwick

    James Chadwick

    Discovered the neutron. Source: Study.com