Atom Timeline

  • Dalton Model

    Dalton Model
    John Dalton concluded that each element is made of atoms that are all alike. Dalton imagined atoms as tiny, solid balls.
  • Thomson Model

    Thomson Model
    British scientist J.J. Thomson purposed the new model suggesting thhat an atom is a positively charged sphere with electrons embedded in it,.
  • Rutherford Model

    Rutherford Model
    British physicist Ernest Rutherford discovered that an atom is mostly empty space and that electrons orbit around a small, positivly charged nucleus.
  • Bohr Model

    Bohr Model
    Danish physicist Niels Bohr proposed a model that showed electrons traveling in specific layers or shells rather than randomly. He said that atoms absorb or give off energy when the electrons move from one shell to another.
  • Chadwick Model

    Chadwick Model
    British physicist James Chadwick discovered the neutron. The neutron explained why atoms were heavier than the total mass of their protons and electrons.
  • The Present Modern Model

    The Present Modern Model
    The current model shows that electrons form a negativly charged cloud around the nucleus.It is impossible to determine exactly where an electron is at a given time.