alpha scattering and the nucleus model

• Atom


  Tiny sphere that cannot be divided
• In 1897, scientists discovered that atoms contain tiny negative particles called electrons
• Plum pudding model

  Atom is a ball of positive charge with negative electrons embedded in it
• Alpha scattering experiment(conducted by Rutherford's)

  1. Fired alpha particles at gold foil

  2. Most alpha particles passed straight through

  3. Some alpha particles were deflected

  4. Some alpha particles bounced straight back
• Results of alpha scattering experiment

  • Atoms are mainly empty space
  • Center of atom has positive charge that repelled alpha particles
  • Mass of atom is concentrated in the center
• Nuclear model

  Most of atom is empty space, with a tiny positive nucleus containing almost all the mass, and negative electrons orbiting the nucleus
• Electron energy levels/shells

  Electrons orbit the nucleus at specific distances
• Proton

  Positive particle in the nucleus
• Neutron

  Neutral particle in the nucleus
• The nuclear model replaced the plum pudding model