• 440 BCE

    Democritus and Lucretius theorized about atoms

    They thought that all objects where were made up of small particles but due to their time, but they could not provide proof of their theory.
  • J.J Thomson

    He discover atoms were made up of smaller components.
  • Rutherford experiment

    Rutherford experiment
    He shoot an Alpha particle at a piece of gold foil. He found out most alpha particles passed through the foil, but a few were bounced backward. This shows atom is empty space surrounding a nucleus
  • Bohr's proposed new model of atom

    He's model of the atom in which the electron was able to occupy only certain orbits around the nucleus.