Radioactivity

• What is the charge of a proton?

  +1
• What is the charge of a neutron?

  0
• What is the charge of an electron?

  -1
• What is the relative mass of a proton?

  1
• What is the relative mass of a neutron?

  1
• What is the relative mass of an electron?

  0.0005
• What is the size of an atom in nanometers?

  ~0.1 nanometers
• What do isotopes of an element have in common?

  Same number of protons
• What defines a neutral atom?

  Same number of electrons and protons
• What is the mass number represented by in isotopes?

  A (number of neutrons and protons)
• What does Z represent in isotopes?

  Proton number
• What happens when an electron gains enough energy?

  It can leave the atom to form an ion
• What occurs when electrons move to a higher orbit?

  The atom absorbs EM radiation
• What occurs when electrons fall to a lower orbit?

  The atom emits EM radiation
• What is alpha decay equivalent to?

  A helium nucleus
• What is the ionizing power of alpha decay?

  Highly ionizing
• What is the penetration power of alpha decay?

  Weakly penetrating
• What is the ionizing power of beta minus decay?

  Medium ionizing
• What is the penetration power of beta minus decay?

  Medium penetration
• What is the ionizing power of gamma radiation?

  Low ionizing
• What is the penetration power of gamma radiation?

  Highly penetrating
• How does photographic film measure radiation?

  Film darkens with radiation exposure
• How does a Geiger-Muller tube detect radiation?

  Transmits electrical pulses with clicks
• Who proposed that everything was made of atoms in 1800?

  Dalton
• Who discovered the electron in 1897?

  JJ Thomson
• What did Rutherford conclude from the Gold Foil Experiment?

  Most of the atom is empty space
• What did Rutherford's model suggest about the atom's charge?

  The overall charge is neutral
• What did Bohr contribute to atomic theory in 1913?

  Final model of the atom
• What happens during beta-minus decay?

  Neutron becomes a proton, releases an electron
• What happens during beta-plus decay?

  Proton becomes a neutron, releases a positron
• What is a gamma ray?

  Electromagnetic radiation
• What is activity in radioactivity?

  Number of decays per second
• What is the unit of activity?

  Becquerel, Bq
• What is half-life?

  Time taken for half the nuclei to decay
• What happens to activity over time?

  Decreases exponentially
• What conclusion did Rutherford make about electron attraction?

  Electrons exist in fixed orbitals
• What are the main components of an atom?

  • Positively charged nucleus
  • Protons
  • Neutrons
  • Negatively charged electrons
  • Nucleus is much smaller than the atom
  • Most mass is in the nucleus
• What are the characteristics of isotopes?

  • Same number of protons
  • Different number of neutrons
  • Different masses
  • Example: Carbon-12, Carbon-13, Carbon-14
• What are the types of radioactive decay?

  • Alpha decay: Helium nucleus, highly ionizing, weakly penetrating
  • Beta Minus decay: Electron, medium ionizing, medium penetration
  • Beta Plus decay: Positron, medium ionizing, medium penetration
  • Gamma decay: Electromagnetic radiation, low ionizing, highly penetrating
• What are the methods of measuring radioactivity?

  • Photographic film: Darkens with radiation exposure
  • Geiger-Muller Tube: Detects radiation with clicks