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Published byArthur Waters Modified over 9 years ago
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Alpha Beta Gamma
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Lesson Contents 1.Physical properties of , and 2.Penetrating power of , and 3.N v Z graphs 4.Decay laws
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Alpha Radiation Alpha particles contain two protons and two neutrons
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Alpha Radiation has the same constitution as a helium nucleus Alpha particles may be written as They have a double positive charge and a mass of 4 u
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Beta-minus Radiation Beta-minus particles are electrons
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Beta-minus Radiation - is produced when a neutron decays Beta-minus particles may be written as They have a negative charge and a mass of 1 / 1800 u
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Beta-minus Radiation - is produced when a neutron decays The surplus mass is released as kinetic energy in the - and as an antineutrino
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Gamma Radiation Gamma rays are a form of electro- magnetic radiation
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Gamma Radiation release is often associated with or decay Gamma rays remove energy from an unstable nucleus
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Beta-plus Radiation + particles are positrons
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Beta-plus Radiation + is produced when a proton decays The surplus mass is released as kinetic energy in the + and as a neutrino
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Penetrating power has a high mass It is stopped by a few centimetres of air has a small mass It is stopped by a few millimetres of aluminium has zero mass It is stopped by thick lead or concrete
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Penetrating power has a high charge It is dangerous if swallowed has a small charge It is dangerous at medium range has high energy It is dangerous at distance
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Penetrating power
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N v Z graphs A Graph of neutron number (N) against proton number (Z) helps to predict whether an isotope will emit or - radiation
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N v Z graphs Isotopes in this region emit particles to become more stable. N decreases by 2 Z decreases by 2
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N v Z graphs Isotopes in this region emit particles to become more stable. N decreases by 1 Z increases by 1
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Decay laws - alpha When an isotope emits an particle Its nucleon number decreases by 4 Its proton number decreases by 2 For example:
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Decay laws – beta-minus When an isotope emits a - particle Its nucleon number is unchanged Its proton number increases by 1 For example:
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Decay laws – beta-plus When an isotope emits a + particle Its nucleon number is unchanged Its proton number decreases by 1 For example:
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Decay laws Try writing the nuclear equations for the decay of these isotopes
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Decay laws Answers
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Alpha Beta Gamma
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