Luke H 9

By LukeHayden
  • 500 BCE

    The Alchemists

    The alchemists thought that all metals were formed by mercury and sulfur.
  • 427 BCE

    Plato

    Plato
    Plato introduced the theory that ideal geometric forms serve as atoms.
  • 400 BCE

    Democritus

    Democritus
    Democritus found that everything was made up of atoms and he thought they were uniform, indestructible, and incompressible.
  • 332 BCE

    Aristotle

    Aristotle
    Aristotle believed that all things were made up of fire, water, earth, and air.

  • Lavoisier

    Lavoisier
    Antoine Lavoisier found how mass was conserved during chemical reactions.

  • John Dalton

    John Dalton
    John Dalton assigned atomic weights to all the 20 elements he knew at the time.

  • Newland's Law of Octaves

    The founder of this was a British chemist named John Newlands. Newlands law of octaves is when elements are arranged by atomic mass every eighth element is similar.

  • Mendeleev's Pd. Table

    Mendeleev's Pd. Table
    He created the periodic table and left gaps for elements that have not been discovered.

  • Photoelectric Effect

    Photoelectric Effect
    Albert Einstein found that increasing the frequency of light made electrons with higher energies.

  • Discovery of Radioactivity

    Discovery of Radioactivity
    Henri Becquerel opened a drawer and discovered spontaneous radioactivity.

  • Discovery of the Electron

    Discovery of the Electron
    The discovery of the electron was by J. J. Thomson. He used cathode ray tubes that showed that all atoms have tiny negatively charged particles.

  • Planck's Quantum Theory of Light

    Planck's Quantum Theory of Light
    According to the theory founded by Max Planck different atoms and molecules can produce or absorb small quantities of energy.

  • Plum Pudding Model

    Plum Pudding Model
    The plum pudding model is electrons surrounded by a positive charge. The model was founded by J. J. Thompson's.

  • Rutherford's Gold Foil Experiment

    Rutherford's Gold Foil Experiment
    Ernest Rutherford hit a piece of gold foil with alpha particles which have a positive charge. Most alpha particles went through this showed that gold was mostly empty space. He concluded that there was a tiny nucleus deflecting some of the alpha particles.

  • Discovery of the Proton

    Discovery of the Proton
    The proton was discovered by Ernest Rutherford. He caused a reaction which led to the splitting of the atom where he found protons.

  • Charge of the Electron

    Charge of the Electron
    Robert Millikan measured the charge of an electron using oil droplets that were negatively charged.

  • Robert Millikan

    Robert Millikan
    He precisely found the magnitude of an electrons charge.

  • Bohr's Planetary Model

    Bohr's Planetary Model
    In Bohr's model the electrons orbit the nucleus of the atom. This was founded by Neils Bohr.

  • Moseley's Atomic Numbers

    Moseley's Atomic Numbers
    Henry Moseley made a paper that stated that an atomic number is the number of positive charges in the nucleus.

  • Schrodinger Equation

    Schrodinger Equation
    It is an equation that governs the wave function of a quantum-mechanical system. Erwin Schrodinger founded the equation.

  • Heisenberg Uncertainty Principle

    Heisenberg Uncertainty Principle
    Werner Heisenberg found that we can not know the position and speed of a particle to an exact accuracy.

  • Discovery of the Neutron

    Discovery of the Neutron
    James Chadwick found the neutron by hitting beryllium with alpha particles from the natural radioactive decay of polonium. The radiation showed penetration through a lead shield which could not be explained.