Atomic Structure ( radiation )

• What are the three subatomic particles in an atom?

  Protons, neutrons, and electrons
• What are the masses of a proton, neutron, and electron?

  Proton = 1, Neutron = 1, Electron = 0
• What are the charges of a proton, neutron, and electron?

  Proton = +1, Neutron = 0, Electron = -1
• Why do atoms have no charge overall?

  They have equal protons and electrons
• Which particle do all atoms of the same element have the same number of?

  Protons
• What does the atomic number tell us?

  It tells us the number of protons
• What does the mass number tell us?

  It tells us the number of protons and neutrons
• What is an isotope?

  Atoms with the same protons but different neutrons
• Describe the early ‘plum pudding’ model of the atom.

  Ball of positive charge with negative electrons
• What two things did Rutherford’s alpha scattering experiment show?

  Mass concentrated in nucleus, nucleus is positive
• Why do some atoms emit radiation from their nucleus?

  Because the nucleus is unstable
• What is alpha radiation?

  2 protons and 2 neutrons
• What is beta radiation?

  Electron
• What is gamma radiation?

  EM wave
• What type of radiation is the most penetrating?

  Gamma
• What type of radiation is the most ionising?

  Alpha
• Why is radiation dangerous?

  It damages cells and may cause cancer
• Which type of radiation is the most dangerous at close range?

  Alpha (most ionising)
• Which type of radiation is the most dangerous at long range?

  Gamma (most penetrating)
• What do we use to measure count rate?

  Geiger Müller tube
• What is the definition of half-life?

  Time it takes for the count rate to half
• What is contamination?

  Unwanted presence of radioactive substance
• What is irradiation?

  Exposure to radiation
• How can we keep safe around radiation?

  • Minimise exposure time
  • Maintain physical distance
  • Use shielding
• What happens to the mass number during alpha decay?

  Mass number decreases by 4
• What happens to the atomic number during alpha decay?

  Atomic number decreases by 2
• What happens to the mass number during beta decay?

  Mass number remains the same
• What happens to the atomic number during beta decay?

  Atomic number increases by 1
• What happens to the mass number during gamma decay?

  No change in mass number
• What happens to the atomic number during gamma decay?

  No change in atomic number
• What are the meanings of key terms related to radiation?

  • Alpha radiation: 2 protons + 2 neutrons
  • Beta radiation: Electron from neutron decay
  • Gamma radiation: High energy electromagnetic wave
  • Half-life: Time for count rate to halve
  • Contamination: Unwanted radioactive substance presence
  • Irradiation: Exposure to radiation