isotopes and nuclear radiation

• what do all atoms have set number of?

  protons
• what is the atomic number?

  the number of protons
• what is the mass number?

  Number of protons and neutrons
• what is an isotope?

  has the same number of protons but different number of neutrons
• do all atoms have different isotopes?

  yes - they usually have one or two stable ones
• what do unstable isotopes do?

  they decay into other elements and give out radiation as they try to become more stable
• what is that process called?

  radioactive decay
• What do radioactive substances spit out?

  one o r more types of ionising radiation from their nucleus - alpha, beta, gamma
• what also can they release?

  neutrons when they decay they rebalance their atomic and mass numbers
• what is ionising radiation?

  is radiation that knocks off electrons off atoms and makes them positive ions
• what is ionising power?

  How easily electrons are knocked off atoms creating positive ions.
• what are the subatomic particles in a alpha particle?

  2 neutrons and 2 protons
• what is an alpha particle the same as?

  helium nucleus
• how far do alpha particles penetrate?

  not very far into materials and they get stopped quickly - they only travel a few cm in air
• what are alpha particles absorbed by?

  sheet of paper
• how ionising are alpha particles?

  Very strongly ionising
• what are beta particles ?

  fast moving electrons - no mass charge of -1
• how ionising are beta particles?

  Moderately ionising
• how far can beta particles penetrate?

  penetrate moderately far into materials before colliding
• what is beta particles range in air?

  a few metres
• how are beta particles absorbed?

  a sheet of aluminium - 5mm thick
• what happens when a beta particle is emitted?

  A neutron turns into a proton
• what are gamma rays?

  they are electromagnetic waves released by the nucleus
• How far do gamma rays penetrate?

  Far into materials without being stopped and will travel a long distance through the air
• what is the ionising power of a gamma ray?

  weakly ionising - they tend to pass through rather than collide with atoms
• what happens they hit something?

  they will do damage
• how are they absorbed?

  thick sheet of lead or meters of concrete