Alpha, beta, gamma radiation

• Atomic structure


  The structure of atoms, including their components and properties
• Types of radiation


  • Alpha
  • Beta
  • Gamma
• Alpha radiation


  • Consists of unstable isotopes that can decay
  • 2 protons and 2 neutrons
  • No electrons
  • Overall charge +2
  • Relatively large
  • Easily stopped
  • Can't penetrate very far into material
  • Only a few cm in air
  • Absorbed by a single sheet of paper
  • Strongly ionising, knocks electrons off atoms it collides with
• Beta particles


  • Electrons
  • Charge -1
  • No mass
  • Emitted when an atom's nucleus decays into an electron and a proton
  • Proton stays in the nucleus
  • Moderately penetrating, can go several meters in air
  • Stopped by 5mm of aluminium
• Gamma rays


  • Waves of electromagnetic radiation
  • Often emitted after alpha or beta particle radiation
  • Weakly ionising
  • Stopped by thick lead
  • Can travel long distances in air
• Radioactive decay


  1. Unstable isotopes

  2. Emission of alpha, beta, or gamma radiation

  3. To become more stable
• Emission of a neutron occurs when an atom has too many neutrons and is unstable, so it throws out a neutron to become more stable