# Explain why the half-life of a radioactive isotope is independent of the temperature of the sample and of the chemical compound in which the isotope is found.

> IB DP Physics Higher Level (2023 syllabus) — E.3 Radioactive decay · Explain · 4 marks

## Mark scheme (4 marks)

1. Radioactive decay is a nuclear process, originating within the nucleus of the atom.
2. Temperature affects only the kinetic energy of atoms / the electron energy levels, which are external to the nucleus.
3. Chemical bonding involves only the outermost electrons and has no effect on nuclear structure or nuclear binding energy.
4. Decay is a random / probabilistic quantum process; the probability of decay per unit time (decay constant) depends solely on the nuclear structure / composition of that nuclide.

## Key terms

- [half-life](https://www.gradenine.co.uk/glossary/half-life)

## Related

- [Revision notes for IB DP Physics Higher Level (2023 syllabus)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-the-half-life-of-a-251c8d39) · Published by Druglandscape Ltd.