History of Atomic theroy

By Tripp_suzannah

  • Democritus

    460-370 BC
    He was the first person to suggest that matter could not be infinitely divided.
    He came up with the term "atoms" to decribe the tiny particles that make up matter and move through empty space,but he could not figure out what holds atoms together.

  • Aristole

    384-322 BC
    He disagreeded with Democritus' idea that atoms can kove through empty space.
    He also denied the existence of atoms due to personal ideas about nature.
    His ideas about matter took over those od Democritus.

  • John Dalton

    1766-1844
    Dalton was an Englsh school teacher who marks the beggning of the development of modern atomic theory.He took Democritus'ideas about matter and revised them based off of his personal scientific rresearch,revised the term atom.

  • The nucleus

    After the gold foil experiment Rutherford came to the conclusion that Thompsons modle of the atom was wrong. He thought that a atom was just a empty space for electrons to move around in. He said the positive charge and the majority of the mass was in the nucleus.

  • The proton and nuetron.

    A proton are posiveky charged subatomic particals while nuetrons carry no electric charge. Chadwick won the 1935 noble peace prize for descovering the nuetron.

  • Sir William Crookes

    He noticed a green flash of light within a carode ray tube while working in a dark lab.Cathrode Ray tube isa glass tube with air removed from the inside chamber connected to an electrical source vis a cathrode and an anode;helps researchers study the relationship between mass and charge.
    Some type of radation striking zinc-sulfide coating inside the tube.Later discovered that the radiation went completey through the tube and not only on the Zn-s coating.This led to the discovery of televison.

  • Physicist J.J. Thompson

    (1856 – 1940)
    He designed a series of CRT experiments at Cambridge to determine the ratio of the particle’s charge to its mass.
    Concluded that the mass of the particle was much less than that of the Hydrogen atom, which disproved Dalton’s theory that atoms were indivisible.

  • Physicist Robert Millikan

    1868 – 1953)
    He designed an oil drop apparatus to determine the charge of the electron.He also determined that the magnitude of the charge of the electron was 1.602x10-19 coulombs and Discovered the mass of the electron using the known charge/mass ratio: 9.1x10-28 g

  • Ernest Rutherford

    Ernest Rutherford (1871 – 1937) studied how positively charged α-particles interacted with solid matter. He designed an experiment to see if α-particles would be deflected as they passed through a thin sheet of gold foil.
    (1871 – 1937) studied how positively charged α-particles interacted with solid matter. He designed an experiment to see if α-particles would be deflected as they passed through a thin sheet of gold foil.