topic 4

• what is a chain reaction

  self sustaining series of reactions
• define fusion

  two nuclei collide at high speed and join to create a heavier nucleus
• define fission

  release of energy from a large and unstable atoms by splitting them into smaller atoms
• 2 ways radation is used in medicine

  x rays

  medical tracers
• define contamination

  unwanted radioactive atoms get onto an object, which may emit radiation
• define irradiation

  exposure to radiation and doesnt make it radioactive
• give two aspects of your life that could affect your radiation dose

  where you live

  what job you have
• define radiation dose

  the risk of harm to body tissues due to exposure to radiation
• what type of nuclear decay doesnt change the mass or charge of a nuetron

  gamma rays
• give alpha, beta and gamma radiations range in the air

  alpha -cms

  beta-a few meters

  gamma- a long distance
• give alpha, beta and gamma radiations ionising power

  alpha- strong

  beta- moderate

  gamma- weak
• name for things that may be emmited during radioactive decay

  alpha particles

  beta particles

  gamma rays

  nuetrons
• what is radioactive decay

  the process of unstable atoms giving out radiation to become more stable
• true or false, isotopes have different mass numbers

  true
• what is the atomic number of an atom

  the number of protons in an atom
• which number defines what element an atom is, atomic or mass

  atomic
• what happens to an atom if it looses one or more of its outer shell electrons

  it becomes positively charged
• true or false, atoms have no overall charge

  true