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      Lesson details

      Learning outcome

      I can describe the properties of alpha, beta and gamma radiation.

      Key learning points

      1. Radioactive particles can emit radiation in the form of particles or gamma radiation.
      2. Ionising radiation forces electrons from atoms, leaving an atom with a positive charge called an ion.
      3. Alpha particles are more ionising than beta or gamma because they have a bigger charge and stronger electric field.

      Keywords

      • Radioactive particle - a particle that can decay and emit nuclear radiation

      • Radiation - emitted by a radioactive nucleus when it decays

      • Ionisation - the removal of one or more outer electrons from an atom

      • Alpha particle - a particle of radiation made from two protons and two neutrons, with a relative charge of +2

      • Beta particle - a particle of radiation made of an electron emitted at high speed from an unstable nucleus

      Common misconception

      Alpha and beta particles and gamma radiation are radioactive.

      Differentiate between radioactive particles that can emit radiation and the radiation itself. Radiation consists of fast moving particles or radiation that can cause ionisation because their electric fields interact with those of outer electrons.

      Teacher tip

      If a radiation kit is available, it can be used to demonstrate the similarities and differences between each type of radiation. Different uses of radiation can be researched and reported on by pupils, perhaps as a homework activity.

      Licence

      This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0
      except where otherwise stated. See Oak's terms & conditions
      (Collection 2).

      Lesson video

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      Prior knowledge starter quiz

      6 Questions

      Q1.
      What part of an atom is identical to a beta-minus particle?

      Correct answer: an electron
      a nucleon
      a neutron
      a proton

      Q2.
      The nucleus of which atom is identical to an alpha particle?

      a hydrogen nucleus
      Correct answer: a helium nucleus
      a lithium nucleus
      a beryllium nucleus

      Q3.
      How is a beta particle emitted from a radioactive atom?

      slowly from an outer electron shell
      at very high speed from an inner electron shell
      slowly from the nucleus
      Correct answer: at very high speed from the nucleus

      Q4.
      What is the mass (nucleon) number of $$^{240}_{94}$$Pu?

      94
      146
      Correct answer: 240
      334

      Q5.
      How many electons are in an atom of $$^{231}_{90}$$Th?

      Correct answer: 90
      141
      231
      321

      Q6.
      How many neutrons are in the nucleus of an atom of $$^{235}_{92}$$U?

      92
      Correct answer: 143
      235
      327

      6 Questions

      Q1.
      Which particles are radioactive?

      alpha particles and beta particles
      alpha particles but not beta particles
      beta particles but not alpha particles
      Correct answer: neither alpha particles nor beta particles

      Q2.
      Why is a beta particle not radioactive?

      It is not harmful.
      Correct answer: It can't decay any further.
      It has no energy.
      It has negative charge.
      It has positive charge.

      Q3.
      How can alpha particles damage atoms they pass sufficiently close to?

      They collide with and break up the atom's nucleus.
      They knock the atom's nucleus out of the atom.
      Correct answer: They pull electrons off atoms they pass close to.
      They destroy the electrons of atoms that they collide with.

      Q4.
      Which of these is the thinnest barrier that can stop most beta particles?

      a single sheet of paper
      the outer layer of a person's skin
      Correct answer: a thin sheet of aluminium
      a thick sheet of lead
      several metres of concrete

      Q5.
      Put these types of radiation in order of how ionising they are, starting with the most ionising.

      1 - alpha particles
      2 - beta particles
      3 - gamma radiation

      Q6.
      Put these types of radiation in order of how penetrating they are, starting with the most penetrating.

      1 - gamma radiation
      2 - beta particles
      3 - alpha particles

      To help you plan your 11 combined science lesson on: Ionising radiation, download all teaching resources for free and adapt to suit your pupils' needs...