Physics 1.5aa-b

• Who first noticed radioactivity and in what year?

  Henri Becquerel in 1896
• What is ionising radiation?


  Radiation emitted from unstable nuclei that can dislodge outer electrons from atoms
• What are the types of radioactive decay?

  • Alpha decay
  • Beta decay
  • Gamma decay
• What is an alpha particle composed of?

  Two protons and two neutrons
• How is an alpha particle represented in notation?


  As \(_{2}^{4}\textrm{He}\) or \(_{2}^{4}\alpha\)
• What happens to the mass number and atomic number during alpha decay?

  The mass number decreases by four and the atomic number decreases by two
• Write the decay equation for alpha decay.


  \(_{Z}^{A}\textrm{X}\rightarrow_{Z-2}^{A-4}\textrm{Y}+_{2}^{4}\textrm{He}\)
• What is a beta particle?

  A fast-moving electron emitted from an unstable nucleus
• What is the relative mass of a beta particle?


  It can be considered to be zero
• What occurs during beta decay in terms of neutron and proton transformation?

  A neutron splits into a positive proton and a negative electron
• What happens to the atomic number and mass number during beta decay?

  The atomic number increases by one while the mass number remains the same
• Write the decay equation for beta decay.


  \(_{Z}^{A}\textrm{X}\rightarrow_{Z+1}^{A}\textrm{Y}+_{-1}^{0}\textrm{e}\)
• What are the key differences between alpha and beta decay?

  • Alpha decay:
  • Emits alpha particles (2 protons, 2 neutrons)
  • Decreases mass number by 4, atomic number by 2
  • Beta decay:
  • Emits beta particles (electrons)
  • Increases atomic number by 1, mass number remains the same
• What is the notation for an alpha particle?


  \(_{2}^{4}\textrm{He}\)
• What are the dangers and uses of radiation?

  • Dangers:
  • Can cause damage to living tissues
  • Can lead to cancer
  • Uses:
  • Medical imaging
  • Cancer treatment
• What is the structure of the atom?

  • Nucleus:
  • Contains protons and neutrons
  • Electron cloud:
  • Contains electrons orbiting the nucleus
• What is the structure of the nucleus?

  • Composed of protons and neutrons
  • Protons have a positive charge
  • Neutrons have no charge
• What is nuclear fission?


  • The splitting of a heavy nucleus into smaller nuclei
  • Releases a large amount of energy
• What is nuclear fusion?


  • The combining of light nuclei to form a heavier nucleus
  • Releases energy