Nucleus

Atomic theory and Subatomic particles

  • 384

    Aristotle

    Aristotle
    Stated that empty space cannot exist and matter is made of the earth, fire, air, and water.
  • 400

    Democritus

    Democritus
    He proposed the idea that matter was not infinitly devisiable. He believed that matter was made up of tiny particles.
  • Period: 400 to

    Atomic Theory

  • Antoine Lavoisier

    Antoine Lavoisier
    Proposed the Law of Conservation of Mass. And stated that matter is neither lost nor gained during a chemical reaction.
  • John Dalton

    John Dalton
    Proposed the atomic theory of Matter. Reasoned that elements were composed of atoms and only whole numbers of atoms can combine to form compounds,
  • Solid Sphere Model

    Solid Sphere Model
    The atom is a solid sphere that cannot be divided up into smaller particles or pieces.
  • J Plucker

    J Plucker
    He built the first Cathode Ray tube, which are used for X-rays.
  • J.J Thomason

    J.J Thomason
    He discovered the electron. And reasoned that atoms contain negatively charged particles, which he called electrons.
  • Plum Pudding Model

    Plum Pudding Model
    The atom can be divided up into a fluid which is stated as a "pudding" and electrons as well. The atom is mostly made up of fluid, that spreads out in the atom that has a postive charge. And the electrons are negatively charged.
  • Ernest Rutherford

    Ernest Rutherford
    Shot tiny positive charged particles at a thin gold foil. He observed that most of the alpha particles went through the foil but few bounced back. And reasoned that there was a massive and postively charge in an atom, called the nucleus.
  • Nuclear Model

    Nuclear Model
    The atom can be divided into the nucleus and electrons. The nucleus is in the center of the atom and has a positive charge. The electron circle the nucleus and have a negative charge.
  • Neils Bohr

    Neils Bohr
    Developed a model of an atom that explained the light given off when elements are exposed to flame or electric fields. He reasoned that the electrons orbit around the nucleus., the electrons in the orbits have different energies.
  • Solar System Model

    Solar System Model
    The atom can be divided into a nucleus and electrons. The nucleus is massive and posively charged. The electrons circle around the nucleus in orbits. The electrons also orbit at a distance from the nucleus.
  • Proton Model

    Proton Model
    The nucleus contains protons. Protons are postive charges. The electrons circle around the nucleus and most of the atom is empty space.
  • Werner Heisenberg

    Werner Heisenberg
    Proposed a cloud model of an atom. He suggested that the location of an electron could not be specified precisely. And the cloud model indicates where you will most likely find a single electron.
  • Electron Cloud Model

    Electron Cloud Model
    An electron cloud surrounds the nucleus, the cloud is made up of fast moving electrons. And the nucleus is made up of protons and neutrons.
  • James Chadwick

    James Chadwick
    Found that the nucleus also included uncharged, or neutral, particles, which he called neutrons. He reasoned that the neutrons were important in holding the positively charged protons together.