Atom

By HeadlessApple

  • Parmenides 550 B.C.

    Parmenides 550 B.C.
    Everything is made up of building blocks

  • Democritus 400 B.C.

    Democritus 400 B.C.
    everything is made of atoms

  • Aristotle 350 B.C.

    all matter is fire, water, earth, and air no one argued because he was popular

  • John dalto 1800

    John dalto 1800
    Daltons atomic theory
    1.all elements are composed of indivisable atoms (false:nuclear reactions)
    2. atoms of the same element are identical (isotopes/ions) the atoms of any one element are different of any other element (true)
    3. atoms make compounds (true)
    4. atoms are rearranged in chemical reactions, not created (true)

  • Dmitri Mendeleev 1897

    first periodic table
    sorted by weights, left gaps for undiscovered elements

  • JJ Thomson 1897

    JJ Thomson 1897
    Discovered electrons
    idea of sub atomic particals
    "cathode ray tube"

  • Milikan

    Found charge and mass of electrons (1/2000 of an atom)
    mass of atom

  • Rutherford

    Rutherford
    positive nucleus with electrons around
    gold foil experiment
    shot alpha particals at golden foil. they should have all gone through but some bounced off

  • Bohr

    Bohr
    Electrons orbited in rings (energy levels) could jump from orbit to orbit to emit energy

  • Chadwick 1932

    Discovered neutrons
    same model as bohr but with neutrons and electrons in nucleus

  • Manhattan project 1941

    Nuclear research
    created atomic bomb for WW2
    seperation of atom