Atomic Structure

• What is half-life in the context of radioactive isotopes?

  Half-life is the time taken for the number of radioactive nuclei in an isotope to halve.
• What does contamination refer to in radioactive materials?

  Contamination refers to radioactive atoms getting into living cells or objects.
• What type of damage can radioactive contamination cause?

  Radioactive contamination can cause tissue damage.
• What is nuclear fusion?

  Nuclear fusion is the process of joining small nuclei together.
• What is nuclear fission?

  Nuclear fission is the splitting of an unstable nucleus.
• What type of radiation are gamma rays?

  Gamma rays are a type of electromagnetic radiation.
• How far can gamma rays travel in air before stopping?

  Gamma rays can travel several meters in air before stopping.
• What can stop gamma rays?

  Gamma rays can be stopped by several centimeters of lead.
• What is ionizing radiation?

  Ionizing radiation is radiation that knocks electrons off atoms, creating positive ions.
• What is a beta particle?

  A beta particle is an electron ejected from the nucleus at very high speed.
• What is the composition of an alpha particle?

  An alpha particle consists of 2 neutrons and 2 protons.
• How far can alpha particles travel before colliding with atoms?

  Alpha particles can travel around 5 cm before colliding with atoms.
• What model did J.J. Thomson propose for the atom?

  1. J. Thomson proposed the plum pudding model of the atom.
• What did Ernest Rutherford contribute to atomic theory?


  Ernest Rutherford proposed the nuclear model of the atom.
• What is background radiation?

  Background radiation is radiation present in food, air, rocks, building materials, and cosmic waste.
• What is the purpose of gamma rays in radioactive decay?

  Gamma rays get rid of excess energy from the nucleus.
• What happens during alpha decay?

  During alpha decay, the charge and mass of the nucleus decrease.
• What is radioactive decay?

  Radioactive decay is the process where unstable isotopes decay into other elements and give out radiation to become more stable.
• What is beta decay?

  Beta decay involves electrons in energy shells moving within the atom and releasing electromagnetic radiation.
• What is activity in the context of radioactive decay?

  Activity is the rate at which unstable nuclei decay.