radioactive decay

• What is the reason some atomic nuclei are unstable?

  Imbalance in the forces within the nucleus
• What happens when an unstable nucleus decays?

  It emits radiation, called nuclear radiation
• What is Carbon-14?

  An unstable isotope of carbon
• How does Carbon-14 differ from Carbon-12?

  Carbon-14 has two extra neutrons
• What is the process of emitting radiation from an unstable nucleus called?

  Radioactive decay
• Why do some isotopes emit radiation?

  To become more stable
• What are the different types of radiation emitted by unstable nuclei?

  Alpha, beta-minus, beta-plus, gamma, neutrons
• What happens to the energy of the nucleus when radiation is emitted?

  The overall energy of the nucleus reduces
• What is the charge of an alpha particle?

  +2
• What is an alpha particle equivalent to?

  A helium nucleus
• What is the charge of beta-minus particles?

  -1
• What are beta-plus particles?

  Fast-moving positrons emitted from the nucleus
• What is the symbol for gamma radiation?

  γ
• How do gamma rays differ from alpha and beta particles?

  Gamma rays are electromagnetic waves
• What is the charge of neutrons?

  Neutral, they have no charge
• What is ionisation?

  Process of an atom losing an electron
• Which type of radiation is the most ionising?

  Alpha radiation
• What is the least ionising form of nuclear radiation?

  Gamma radiation
• What are the properties of alpha, beta, and gamma radiation?

  • Alpha: least penetrating, stopped by paper
  • Beta: stopped by a few mm of aluminium
  • Gamma: most penetrating, requires several meters of concrete or cm of lead
• How does the range of radiation types differ in air?

  Alpha travels a few cm, beta tens of cm, gamma infinite range
• What is background radiation?

  Radiation that exists around us all the time
• What are the two types of background radiation?

  Natural sources and man-made sources
• What is a natural source of background radiation?

  Radon gas from rocks
• How does cosmic radiation reach Earth?

  From the sun and high-energy cosmic events
• What is a man-made source of background radiation?

  X-rays and CT scans
• How is corrected count rate determined?

  By subtracting background radiation from total readings
• What unit measures the dose of radiation?

  Sieverts (Sv)
• What does a Geiger-Müller tube do?

  Measures and detects radiation
• What happens during beta-minus decay?

  A neutron changes into a proton and an electron
• What is the result of beta-minus decay on atomic number?

  The atomic number increases by one
• What is emitted during beta-plus decay?

  A positron
• What happens to the atomic number during beta-plus decay?

  The atomic number decreases by one
• What occurs when an alpha particle is emitted from a nucleus?

  The atomic number decreases by two
• What are the key differences between beta-minus and beta-plus decay?

  • Beta-minus: neutron to proton, emits electron
  • Beta-plus: proton to neutron, emits positron
  • Both keep mass number the same
• What changes occur during alpha emission?

  • Loses 2 protons and 2 neutrons
  • Atomic number decreases by 2
  • Mass number decreases by 4
• What happens to the atomic number during decay when r stays the same?

  It decreases by one
• What is the mass number of a positron?

  0
• Why do positrons have a mass number of 0?

  They have negligible mass compared to neutrons
• What happens to the mass number of decaying nuclei?

  It remains the same
• What is the atomic number of positrons?

  +1