Development of the Atomic Theory Assignment

  • 201

    382 BCE, Aristotle

    382 BCE, Aristotle
    He believed that you would never end up with a particle that would never be cut.
  • 202

    440 BCE, Democritus

    440 BCE, Democritus
    Democritus believed that you would eventually get a particle so small that it could not be cut called an atom. The word atom comes from the Greek word atomos. He also said that atoms are small hard particles. In addition to that he thought that atoms were made from a single material formed into different states.
  • John Dalton

    John Dalton
    John Dalton was a British school teacher and Chemist. He wanted to know why elements combine in certain proportions based on mass form compounds. His research concluded that.
    • All substances are made of atoms, atoms are small particles that cannot be created, divided, or destroyed.
    • Atoms of the same element are exactly alike, and atoms of different elements are different.
    • Atoms join with other atoms to make new substances.
  • Thomson

    J.J. Thomson discovered that there was one mistake in Dalton’s theory. He discovered that there are small particles inside the atom. There for he concluded that an atom can be divided into smaller parts. He experimented with a cathode-ray tube. He learned that a positively charged plate attracted the beam. These results concluded that the beam was made of particles he called electrons. Electrons are a subatomic particle that has a negative charge.
  • Rutherford

    He designed an experiment to study the parts of an atom. He did this by aiming a beam of small positively charged particles at a thin sheet of gold. Then he put a special coated peace of tin foil behind it so the coating would glow when it was hit. He was surprised when some of the particles did not go straight through some even cam straight back.
  • Rutherford

    He made a new model where he proposed that the center of an atom a tiny extremely dense positively charged part called the nucleus. He reasoned that positively charged particles that passed close by the nucleus were pushed away by the positive charges in the nucleus.
  • Bohr

    In his model there are no paths between energy levels but electrons can jump from a path in one level to another level. Such as when you climb up the rungs on a latter you go to a different level.
  • Schrodinger and Heisenberg

    Schrodinger and Heisenberg
    They further explained the nature of electrons in the atom. Such as when they said the exact path of an electron cannot be determined.