Nuclear Equations (Edexcel GCSE Physics): Revision Note

Nuclear Equations

Use given data to balance nuclear equations in terms of mass and charge

• Nuclear radioactive decay equations show the changes in mass and charge of the nuclei in the decay

• Each term will have the chemical symbol of the element or the type of radiation

Nuclear notation

• The top number A represents the nucleon number or the mass number

  • Nucleon number (A) = total number of protons and neutrons in the nucleus

• The lower number Z represents the proton or atomic number

  • Proton number (Z) = total number of protons in the nucleus

• Nuclear equations, just like chemical equations, balance:

  • The sum of the nucleon (mass) numbers on the left of each equation should equal the sum on the right

  • The sum of the proton (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 nucleon number of the daughter nucleus is 4 less than the parent

  • The proton number of the daughter nucleus is 2 less than the parent

Alpha decay equation

Beta Minus Decay Equation

• In nuclear equations representing beta minus decay:

  • The nucleon number of the daughter nucleus is the same as the parent

  • The proton number of the daughter nucleus is 1 more than the parent

Beta-minus decay equation

Beta Plus Decay Equation

• In nuclear equations representing beta plus decay:

  • The nucleon number of the daughter nucleus is the same as the parent

  • The proton number of the daughter nucleus is 1 less than the parent

Beta-plus decay equation

Gamma Decay Equation

• In nuclear equations representing gamma decay:

  • The nucleon number of the daughter nucleus is the same as the parent

  • The proton number of the daughter nucleus is the same as the parent

Gamma decay equation