Nuclear reactions and the conservation laws they obey sheet3-mark answer frameExplain what a nuclear reaction is, with one example, and list the laws it must obey.
How to lay out the answer. Follow the frame, then write it in your own words.
- 1 · Define it. A reaction in which nuclei interact and change into new nuclei (transmutation), with energies of the order of MeV.
- 2 · Give an example. Rutherford (1919): ⁴₂He + ¹⁴₇N → ¹⁷₈O + ¹₁H.
- 3 · State the laws.
- Mass number conserved: 4 + 14 = 17 + 1
- Atomic number (charge) conserved: 2 + 7 = 8 + 1
- Mass-energy conserved
- Linear momentum conserved
- 4 · Contrast with a chemical reaction. A chemical reaction moves only valence electrons and involves a few eV.
- 5 · Close in one line. So, balancing A and Z lets us complete any nuclear equation.
Scoring tip: Check A and Z on both sides under your example; showing the sums earns the marks.
