AlphaBeta

Gamma

AlphaBeta

Gamma

Lesson ContentsLesson Contents1. Physical properties of ,

and 2. Penetrating power

of,and3. N v Zgraphs4. Decay laws

Alpha RadiationAlpha RadiationAlpha particles contain two protons and two neutrons

Alpha RadiationAlpha Radiation has the same constitution as a helium nucleusAlpha particles may be written as

They have a double positive charge and a mass of 4 u

Beta-minus RadiationBeta-minus RadiationBeta-minus particles are electrons

Beta-minus RadiationBeta-minus Radiation- is produced when a neutron decaysBeta-minus particles may be written as

They have a negative charge and a mass of 1/1800 u

Beta-minus RadiationBeta-minus Radiation

- is produced when a neutron decays

The surplus mass is released as kinetic energy in the - and as an antineutrino

Gamma RadiationGamma RadiationGamma rays are a form of electro-magnetic radiation

Gamma RadiationGamma Radiation release is often associated with or decayGamma rays remove energy from an unstable nucleus

Beta-plus RadiationBeta-plus Radiation+ particles are positrons

Beta-plus RadiationBeta-plus Radiation+ is produced when a proton decays

The surplus mass is released as kinetic energy in the + and as a neutrino

Penetrating powerPenetrating power has a high massIt is stopped by a few centimetres of air has a small massIt is stopped by a few millimetres of aluminium has zero massIt is stopped by thick lead or concrete

Penetrating powerPenetrating power has a high chargeIt is dangerous if swallowed

has a small chargeIt is dangerous at medium range has high energyIt is dangerous at distance

Penetrating powerPenetrating power

N v Z graphsN v Z graphsA Graph of neutron number (N) against proton number (Z) helps to predict whether an isotope will emit or -

radiation

N v Z graphsN v Z graphsIsotopes in this region emit particles to become more stable.N decreases by 2Z decreases by 2

N v Z graphsN v Z graphsIsotopes in this region emit particles to become more stable.N decreases by 1Z increases by 1

Decay laws - alphaDecay laws - alphaWhen an isotope emits an particle Its nucleon number decreases by 4 Its proton number decreases by 2For example:

Decay laws – beta-minus

Decay laws – beta-minus

When an isotope emits a- particle Its nucleon number is unchanged Its proton number increases by 1For example:

Decay laws – beta-plus

Decay laws – beta-plus

When an isotope emits a+ particle Its nucleon number is unchanged Its proton number decreases by 1For example:

Decay lawsDecay lawsTry writing the nuclear equations for the decay of these isotopes

Decay lawsDecay lawsAnswers

AlphaBeta

Gamma

AlphaBeta

Gamma