Chapter 20
Radioactivity
Radioactive emissions come from changes inside an unstable nucleus.
Spaced review
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Atoms, nuclei and isotopes
Read a nuclide symbol, count particles and identify isotopes.
Radioactive decay and radiation
Explain random, spontaneous decay and compare the nature, ionisation and penetration of three emissions.
Nuclear decay equations
Balance nucleon and charge numbers and follow successive nuclear changes.
Background radiation and activity
Correct count rates for background and distinguish a detector reading from source activity.
Half-life from numbers and graphs
Use repeated halving and corrected decay curves to find activity or elapsed time.
Uses and hazards
Use half-life, penetration and ionisation to compare sources and explain applications and hazards.
Fission and fusion
Distinguish splitting heavy nuclei from joining light nuclei and explain energy release from suitable nuclear fuels.