6.2 - Alpha, Beta & Gamma Radiation

• What are isotopes?

  Different forms of an element with varying neutrons
• What is the key characteristic of isotopes?

  Same number of protons, different neutrons
• What does it mean for an isotope to be unstable?

  It can undergo radioactive decay
• What happens during radioactive decay?

  Isotopes emit particles to become stable
• What does it mean if a material is radioactive?

  It consists of unstable isotopes that decay
• What are the four types of nuclear radiation?

  • Alpha particles
  • Beta particles
  • Gamma rays
  • Neutrons
• What are alpha particles made of?

  Two protons and two neutrons
• What is the nuclear symbol for alpha particles?

  He
• What is the charge of alpha particles?

  Two plus
• Why can alpha particles not penetrate far into materials?

  They are relatively large and easily stopped
• How far can alpha particles travel in the air?

  A few centimeters
• What can stop alpha particles?

  A single sheet of paper
• What does it mean for alpha particles to be strongly ionizing?

  They can easily knock off electrons from atoms
• What are beta particles?

  Electrons emitted from decaying neutrons
• What is the charge of beta particles?

  Negative one
• How are beta particles emitted?

  From a neutron decaying into a proton and electron
• How far can beta particles penetrate materials?

  Several meters of air or five millimeters of aluminum
• What are gamma rays?

  Waves of electromagnetic radiation
• Why are gamma rays weakly ionizing?

  They have no mass or charge
• How far can gamma rays travel through materials?

  Long distances, requiring thick lead to stop
• What happens when a nucleus emits a neutron?

  It increases stability by reducing neutrons
• What are the key differences between alpha, beta, and gamma radiation?

  • Alpha:
  • Made of two protons and two neutrons
  • Stopped by paper
  • Strongly ionizing
  • Beta:
  • Electrons emitted from neutrons
  • Stopped by aluminum
  • Moderately ionizing
  • Gamma:
  • Electromagnetic waves
  • Stopped by lead
  • Weakly ionizing
• What is the main purpose of gamma rays being emitted?

  To release extra energy from the nucleus
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• A radioactive material has unstable isotopes that can decay.
• What does an alpha particle consist of?

  • Two neutrons
  • Two protons
• An alpha particle is the same as a helium nucleus. It has no electrons, and has a charge of 2+.
• What does a beta particle consist of?

  One electron
• What does a gamma ray consist of?

  Electromagnetic radiation
• No charge: C

  Positive charge: A

  Negative charge: B

  
• What causes the emission of a neutron?

  A nucleus has too many neutrons making it unstable
• Cannot penetrate paper: A

  Can penetrate paper but cannot penetrate 5 mm of aluminium: B

  Can penetrate aluminium but cannot penetrate thick lead: C

  
• A beta particle is the same as an electron. What is the source of the beta particle?

  A neutron decaying into a proton and an electron
• Weakly ionising: C

  Moderately ionising: B

  Strongly ionising: A