The structure of atoms: 9.2.4 - Isotopes


  • To know that most elements have atoms which may have different number of neutrons
  • To know that the relative mass of an element is the weighted average mass of its isotopes compared to the mass of a 12C atom/12.
  • To be able to calculate the relative atomic mass given the isotopic masses and relative abundances
  • To be able to calculate the relative abundances of the isotopes given the relative atomic mass and the isotopic masses.
  • To know that some isotopes are unstable and decay releasing radiation.
  • To understand that radiation has three common forms.
  • To understand that radiation is harmful to life.
  • To know that radioisotopes have many uses in society.


Teacher directed


Student follow up

Research the uses of isotopes in society.


Teacher's notes

Discussion including:

  • smoke detectors
  • radiocarbon dating
  • thickness measurement
  • pipeline leakage detection
  • atomic energy


Isotopes 1 - flash presentation

Isotopes 2 - flash presentation

Next Page

IsisSoft 2014