Atomic structure

• What is the definition of activity in nuclear physics?

  The rate at which an unstable nucleus decays
• What is an alpha particle composed of?

  Two protons and two neutrons
• What does the atomic number represent?

  The number of protons in an atom
• Why does each element have a different atomic number?

  Each element has a unique number of protons
• What is background radiation?

  Radiation from natural and man-made sources
• What unit measures radioactive activity?

  Becquerel
• What is a beta particle?

  A high-speed electron emitted from a nucleus
• What does the Bohr model suggest about electrons?

  Electrons orbit the nucleus at set distances
• What does count-rate measure?

  The number of decays per second
• What are electrons in an atom?

  Negatively charged constituents found in energy levels
• How do electrons transition between energy levels?

  By absorbing or emitting electromagnetic radiation
• What is a chain reaction in nuclear physics?

  Neutrons inducing further fission in nuclei
• What are fission products?

  Two smaller nuclei, neutrons, and gamma rays
• What is a gamma ray?

  Electromagnetic radiation emitted from a nucleus
• What is a Geiger-Muller tube used for?

  Measuring the count-rate of radioactive samples
• What is half-life in nuclear physics?

  The time for unstable nuclei to halve
• What are ions?

  Atoms with a resultant charge from electron loss or gain
• What is irradiation?

  Exposure of an object to nuclear radiation
• What is the charge of the nucleus in an atom?

  Positively charged
• What are isotopes?

  Atoms with the same protons but different neutrons
• What particles are found in the nucleus?

  Neutrons and protons
• What is the charge of an electron?

  Negative
• How does the mass number differ from the atomic number?

  Mass number includes protons and neutrons
• What is the relative mass of a proton?

  1
• What are negative ions?

  Atoms that gained electrons and have a negative charge
• What is the relative charge of a neutron?

  0
• What are neutrons?

  Neutrally charged constituents of the nucleus
• What is the typical radius of an atom?

  $1 \times 10^{-10} \text{ metres}$
• What causes nuclear explosions?

  An uncontrolled chain reaction producing vast energy
• How does the radius of the nucleus compare to the radius of an atom?

  The nucleus is 10,000 times smaller
• What is nuclear fission?

  Splitting a large nucleus into smaller nuclei
• Where is most of the mass of an atom concentrated?

  At the nucleus
• What is nuclear fusion?

  Joining two small nuclei to form a larger one
• What is the arrangement of electrons in an atom?

  • Electrons lie at different distances from the nucleus
  • They occupy different energy levels
  • Arrangements may change with EM radiation interaction
• What is the nucleus of an atom?

  The positively charged center containing protons and neutrons
• What do all atoms of the same element have in common?

  The same number of protons
• What does the plum pudding model represent?

  An atom as a ball of positive charge with electrons
• What defines a neutral atom?

  It has the same number of electrons and protons
• What are isotopes?

  Atoms of the same element with different masses
• What are positive ions?

  Atoms that have lost electrons and have a positive charge