IB Physics SL E.3.7 Decay nuclear changes Question Bank
Practise IB Physics SL/HL E.3.7 by applying decay nuclear changes concepts to exam-style physics questions.
- Syllabus
- First assessment 2025
- Course
- Physics SL
- Level
- SL
Practise IB Physics SL/HL E.3.7 by applying decay nuclear changes concepts to exam-style physics questions.
Thallium-205 (81205Tl) can also form from successive alpha ( α ) and beta-minus ( β−) decays of an unstable nuclide. The decays follow the sequence αβ−β−α. The diagram shows the position of 81205Tl on a chart of neutron number against proton number.

Draw four arrows to show the sequence of changes to N and Z that occur as the 81205Tl forms from the unstable nuclide.
any α change correct
any β change correct
diagram fully correct
Award [2 max] for a correct diagram without arrows drawn.
For MP1 accept a (-2, -2) line with direction indicated, drawn at any position in the graph.
For MP2 accept a (1, -1) line with direction indicated, drawn at any position in the graph.
Award [1] max for a correct diagram with all arrows in the opposite direction