Atomic Theories and Ideas Changing Through Time

By kateadams14
  • 400

    Democritus

    Democritus
    • All things are composed of invisible tiny particles of matter, which can’t be destroyed.

  • John Dalton

    John Dalton
    • Described tiny indivisible particles called atoms.
    • Atoms can’t be divided or destroyed.
    • Atoms can join together to form molecules.
    • Atoms of one element are all the same.

  • J. J. Thompson

    J. J. Thompson
    • Atoms contain electrons, which have a negative charge.
    • Atoms are solid with electrons and protons randomly placed through them.

  • Ernest Rutherford

    Ernest Rutherford
    • Atoms have a dense nucleus which contains protons, and most of the rest is empty space.
    • Electrons orbit around the nucleus like planets around the sun.

  • Neils Bohr

    Neils Bohr
    • Electrons are arranged in layers or shells around the nucleus.
    • The shells have different energy levels, and electrons fill up the lowest levels first.

  • James Chadwick

    James Chadwick
    • The nucleus also contains neutrons, which are unchanged particles with a similar mass to protons.