Alpha scattering experiment

• What should you be able to describe by the end of the video?

  The plum pudding model of atomic structure and the alpha scattering experiment
• What did the ancient Greeks believe about atoms?

  They believed that everything is made of tiny, indivisible spheres called atoms
• When was the electron discovered?

  In 1897
• What did the discovery of electrons indicate about atoms?

  Atoms are not tiny spheres that cannot be divided; they have an internal structure
• What is the name of the model that describes atoms as a ball of positive charge with negative electrons embedded in it?

  The Plum Pudding model
• Why did scientists conduct the alpha scattering experiment?

  To determine if the plum pudding model was correct
• What material did scientists use for the alpha scattering experiment?

  Gold foil
• Why was gold chosen for the alpha scattering experiment?

  Because it can be hammered into very thin foil just a few atoms thick
• What are the particles fired at the gold foil in the alpha scattering experiment called?

  Alpha particles
• What charge do alpha particles have?


  Positive charge
• What did scientists conclude from the fact that most alpha particles passed straight through the gold foil?

  Atoms are mainly empty space
• What did the deflection of some alpha particles indicate?

  The center of the atom must have a positive charge
• What does it mean if an alpha particle bounces straight back off the gold foil?

  The center of an atom must contain a great deal of mass
• What is the central part of an atom called?

  The nucleus
• How did the results of the alpha scattering experiment affect the plum pudding model?

  It led to the replacement of the plum pudding model with the nuclear model
• What are the key features of the nuclear model of atomic structure?

  • Most of the atom is empty space
  • A tiny positive nucleus at the center
  • The nucleus contains most of the mass of the atom
  • Negative electrons orbit around the nucleus
• What will be covered in the next video?

  A more detailed look at the nuclear model of atomic structure
• Where can students find questions on this topic?

  In the vision workbook linked in the video