• 427 BCE

    Plato

    Plato
    objects of matter have to derive atoms from 1 of 5 different solid objects.
  • 400 BCE

    democritus

    democritus
    he thought that everything was made from atoms
  • 384 BCE

    aristotle

    aristotle
    he believed that everything was made out of the four atoms, earth fire water and air. he did not believe that things were made out of atoms.
  • robert boyle

    robert boyle
    he believed that gas' volume decreases when pressure increases
  • lavoisier

    lavoisier
    everything's total mass is always the same
  • john dalton

    john dalton
    he believed that atoms were the smallest particles of matter and also that they cannot be created or destroyed. also that all atoms of the same element were the same
  • the alchemists

    the alchemists
    they made some parts of chemistry that is used today. some of it is instruments, some is what melts different substances.
  • dmitri mendeleev

    dmitri mendeleev
    when all elements are put together in numerical order it can form a pattern
  • robert millikan

    robert millikan
    quantifying an electrons charge
  • JJ Thompson

    JJ Thompson
    found electrons
  • photoelectric effect

    photoelectric effect
    when light with a certain energy hit a metal an electron may be locked loose
  • einstein

    einstein
    einstein proved that atoms exist mathemathically he also proved liquids are made of molecules
  • plancks quantum theory of light

    plancks quantum theory of light
    the energy of light is proportional to the frequency
  • the curies

    the curies
    they discovered polonium and radium
  • ernest rutherford

    ernest rutherford
    atoms are mostly hollow and that the majortiy of their matter comes from the nucleus.
  • henry g j moseley

    henry g j moseley
    the atomic numberis number of positive charges in the nucleus of an atom
  • werner heisenberg

    werner heisenberg
    he developed the electron cloud model
  • shrodinger equation

    wave equation
  • neils bohr

    neils bohr
    he created the model of the atom
  • james chadwick

    james chadwick
    exsistance of neutrons