Decay Equations

• Writing Decay Equations

  • Nuclear radioactive decay equations show the changes in mass and charge of the nuclei in the decay
  • Nuclear equations, just like chemical equations, balance:
  • The sum of the mass numbers on the left of each equation should equal the sum on the right
  • The sum of the atomic numbers should also balance on the left and right
  • The parent nucleus is the nucleus that decays
  • Subsequently, the daughter nucleus remaining after the decay
• Alpha Decay Equation

  • In nuclear equations representing alpha decay:
  • The mass number of the daughter nucleus is 4 less than the parent
  • The atomic number of the daughter nucleus is 2 less than the parent

  
• Alpha Decay Equation

  • The following equation shows Polonium-212 undergoing alpha decay
  • It forms Lead-208 and an alpha particle
  • An alpha particle can also be written as a helium nucleus (Symbol He)
• The polonium nucleus emits an alpha particle, causing its mass and charge to decrease. This means it changes into a new element

  
• Beta Minus Decay Equation

  • In nuclear equations representing beta minus decay:
  • The mass number of the daughter nucleus is the same as the parent
  • The atomic number of the daughter nucleus is 1 more than the parent
• Beta-minus decay equation

  
• • The following equation shows carbon-14 undergoing beta decay
  • It forms nitrogen-14 and a beta particle
  • Beta particles are written as an electron in this equation

  
• Gamma Decay Equation

  • In nuclear equations representing gamma decay:
  • The mass number of the daughter nucleus is the same as the parent
  • The atomic number of the daughter nucleus is the same as the parent

  
• • Here is an example of Uranium-238 undergoing gamma decay
  • Notice that the mass number and atomic number of the unstable nuclei remains the same during the decay