IB Physics SL E.3.8 Radioactive Decay Equations

Practise completing nuclear decay equations by conserving nucleon number, charge and lepton number and including the correct electron, positron, neutrino or photon products.

Exam points

balance A and Z on both sides before identifying the missing daughter or emitted particle
include an antineutrino in β⁻ decay and a neutrino in β⁺ decay with correct lepton number
represent gamma decay as nuclear de-excitation with unchanged A and Z plus a photon

[Maximum number: 2]

This section consists of three questions: B1, B2 and B3.

A nucleus of tritium decays to a nucleus of helium-3. Identify the particles X and Y in the nuclear reaction equation for this decay.

{ }_{1}^{3} \mathrm{H} \rightarrow{ }_{2}^{3} \mathrm{He}+\mathrm{X}+\mathrm{Y}

X:
Y:

$\beta^{-}$ or ${ }_{-1}^{0} \mathrm{e}$ or $\mathrm{e}^{-}$ or electron or beta particle;
$\bar{v}$ or ${ }_{0}^{0} \bar{v}$ or antineutrino;

Marking guidance:

Allow answers in either order.

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E.3.8—Decay equations question 1