Atomic structure

• What are the 4 types of nuclear radiation?

  -Alpha particles

  -gamma particles

  -beta particles

  -neutrons
• What are alpha particles made up of?

  -2 protons and 2 neutrons (helium nucleus)
• What do alpha particles not have?

  Electrons
• What is the overall charge of an alpha particle?

  2+
• What are beta particles?

  High-speed Electrons
• What are Gamma rays?


  electromagnetic radiation
• How far can alpha particles travel in air ?

  A few cm
• What are alpha particles absorbed by?

  A sheet of paper
• How ionising are alpha particles?

  They are strongly ionising
• How ionising are beta particles?

  Moderately ionising
• How far can beta particles travel in the air?

  A few meters
• What are beta particles absorbed by?

  A sheet of aluminium
• How far do gamma rays penetrate into materials?


  Very far
• What are gamma rays absorbed by?


  Thick sheets of lead
• How ionising are gamma rays?

  Weakly ionising
• How long can gamma rays travel in the air?

  A long way
• How far do alpha particles penetrate into Materials ?


  Not very far
• What does ionising mean?


  The process of converting an atom or molecule into an ion by adding or removing electrons.
• How are Nuclear equations written?

  Total mass--> atom(s) after decay + radiation emitted
• What happens in a beta decay?


  A neutron in the nucleus turns into a proton and release a fast moving electron
• What is radioactive decay?


  Random
• What is the half life?


  The half-life of a radioactive isotope is the time it takes for the number of nuclei of the isotope in a sample to halve
• What is Activity?


  Activity is the rate at which a source of unstable nuclei decays.
• What is activity measured in?


  becquerel (Bq)
• What device is used to measure radiation?

  Geiger-Muller counter
• What is the count rate?

  Count-rate is the number of decays recorded each second by a detector