Radiation

• What are isotopes?

  Different forms of the same element
• How do isotopes of an element differ?

  By the number of neutrons they have
• What does it mean for an isotope to be unstable?

  It can undergo radioactive decay
• What is radioactive decay?

  Emission of particles to become stable
• What does it mean if a material is radioactive?

  It consists of unstable isotopes
• 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
• How are alpha particles represented?

  With helium's nuclear symbol, 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 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
• What are beta particles?

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

  • 1
• How do beta particles originate in an atom?

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

  Several meters of air or 5 mm of aluminum
• What are gamma rays?

  Waves of electromagnetic radiation
• How do gamma rays behave when emitted?

  They pass straight through materials
• What makes gamma rays weakly ionizing?

  They have no mass or charge
• What materials can stop gamma rays?

  Thick sheets of lead or concrete
• What happens when a nucleus emits a neutron?

  It increases stability by reducing neutrons
• What are the key characteristics of the four types of nuclear radiation?

  • Alpha particles:
  • Made of 2 protons, 2 neutrons
  • Stopped by paper
  • Strongly ionizing
  • Beta particles:
  • Electrons with charge -1
  • Stopped by aluminum
  • Moderately ionizing
  • Gamma rays:
  • Electromagnetic waves
  • Stopped by lead/concrete
  • Weakly ionizing
  • Neutrons:
  • Emitted to increase stability
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