topic 4

    Cards (19)

    • john daltons model was in 1804
    • rutherford experiment was in 1909
    • unstable elements usually decay into other elements and give out radiation as they try to become more stable - this process is called radioactive decay
    • radioactive substances spit out 1+ types of ionising radiation from the nucleus
    • ionising radiation is radiation that knocks off electrons from atoms
    • alpha radiation is when alpha particles are emitted from the nucleus
    • alpha particles have 2 neutrons and 2 protons
    • alpha particles dont penetrate very far into materials - only a few cm in the air and can be absorbed by a piece of paper
    • alpha particles are very ionising becuase of the size
    • alpha particles are used in smoke detectors as it ionises the air particles causing a current to flow and if there is smoke in the air it binds to the ion making the current stop causing an alarm
    • beta particles are high speed electrons
    • beta particles have virtually no mass and a chare of -1
    • beta particles are moderately ionising
    • beta particles could be absorbed by 5mm thick aluminium
    • for every beta particle emitted a neutron in the nucleus has turned into a proton
    • beta particles can be used to test thickness of sheets of metal
    • gamma rays are electromagnetic waves with a short wavelength
    • gamma rays can travel a long way through air and can penetrate a long way without being stopped
    • gamma rays are weakly ionising as they pass through things instead f colliding
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