Half lives and the random nature of radioactive decay

• Describe the nature of radioactive decay

  • random
  • which nuclei decays and when is determined only by chance
  • it is impossible to predict which nuclei will decay and when
• Define the half-life of a radioactive isotope

  • The time it takes for the number of unstable nuclei in a substance to halve
  • the time it takes for the count rate from a sample to fall to half its initial level