understang radioact

• Radioactive decay


  The process by which an unstable atomic nucleus loses energy by emitting radiation
• Radioactive decay can result in the transformation of one element into another
• Types of radioactive decay

  • Alpha
  • Beta
  • Gamma
• Alpha decay


  • Unstable nucleus emits an alpha particle which consist of 2 protons and 2 neutrons
  • Large and heavy
  • Low penetrating power but has high ionizing
  • Can be stopped by papers
  • Positively charged and have relatively low penetrating power
  • Ionize atoms they encounter along their path, leading to potential damage in biological tissues
• Isotopes undergoing alpha decay

  • Uranium-238(U-238) to Thorium (Th-234)
• Beta decay


  • Emits electrons or positrons, transforming neutrons into protons and releasing electrons and antineutrinos
  • Higher penetration power than alpha particles
  • Beta minus decay: neutron within the nucleus is transformed into a proton; increases atomic number by 1 while keeping the mass constant
  • Beta plus decay: proton is transformed into neutron; decreases the atomic number by 1 while keeping the mass constant
  • Can penetrate further than alpha particles
  • Can be stopped by aluminum or plastic
• Isotopes undergoing beta decay

  • Beta minus: Carbon-14 (C-14) to Nitrogen-14(N-14)
  • Beta plus: Protactinium-91(Pa-91) to Thorium-90(Th-90)
• Gamma decay


  • High penetration power but low ionizing
  • Does not change the mass or atomic number
  • Electromagnetic radiation similar to x-rays but with higher energy
  • Can pass through the human body, causing damage to cells and DNA
• Isotopes undergoing gamma decay

  • Cobalt-60 (Co-60)