LuduminaAT-04 · AT-U2 · Planned
Balancing nuclear equations
Learning objectives
Balance A and Z for alpha/beta/gamma decay; explain why gamma changes neither.
8463 §§4.4.2.2 / 8464 §§6.4.2.2
DfE single-science pp.43–44 / Combined pp.35–36. Evidence checked 30 September–1 October 2026. Skills: WS1.2,4.1; MS1b,3c.
Needs firstAT-03
Explanation
A nuclear equation balances nucleon number and charge/atomic-number bookkeeping. Alpha decay lowers A by four and Z by two. Beta-minus changes a neutron into a proton and emitted electron, raising the daughter’s Z by one without changing A. Gamma changes neither.
Concepts, equations and units: A/Z bookkeeping; alpha ⁴₂He, beta ⁰₋₁e; beta-minus neutron→proton in nucleus; element identity changes when Z changes.
Prediction, demonstration and game exercise
Predict, observe, explain
Demonstrate a worked alpha and beta decay; keep nucleon-number balance separate from electric charge notation.
Planned learner game exercise
Place missing daughter/emission tiles in nuclear equations and verify both balances.
Independent practice
Four equation completions plus one explanation of gamma decay.
Original practice example · Shared
A nucleus with A = 210 and Z = 84 emits an alpha particle. Give daughter A and Z.
Show working and model answer
Working / reasoning
A_daughter = 210 − 4; Z_daughter = 84 − 2.
Answer
A = 206, Z = 82.
Exit check and success criteria
Three equations correct and gamma changes neither A nor Z.
During practice, compare the prediction with evidence and give an error-specific prompt. The exit item uses a fresh context or fresh values, answered independently.
Misconceptions, practical links and mastery
Check these misconceptions
Beta emission lowers daughter Z; atomic mass number means electron count; gamma removes a proton.
Practical preparation
No RP; symbolic practice.
Virtual preparation and revision only. Required hands-on activities and school records remain separate.
Proposed mastery
0: not yet evidenced. 1: supported. 2: independent exit criteria met. 3: successful changed-context transfer. Advance at 2; revisit with fresh retrieval. These are not GCSE grades.