Answer: Energy released (or absorbed): Q = (mass_reactants - mass_products) × c².
- A The total kinetic energy carried by the reactants before collision
- B Energy released (or absorbed): Q = (mass_reactants - mass_products) × c²
- C The half-life of the radioactive product nucleus formed
- D The activity (decay rate) of the resulting product nucleus
Correct answer: B. Energy released (or absorbed): Q = (mass_reactants - mass_products) × c²
Explanation: Q-value: Q = (M<sub>reactants</sub> - M<sub>products</sub>)c². Positive Q = exothermic (energy released). Negative Q = endothermic.
Binding energy per nucleon rises sharply for light nuclei, peaks around iron-56 (the most stable nucleus), then slowly declines for heavier nuclei - which is exactly why fusing light nuclei or splitting heavy nuclei both release energy: each moves the products toward this stability peak.
Concept context
Radioactivity, nuclear reactions, fission, fusion, and binding energy.