CIE iGCSE Co-Ordinated Science P5.2.3 Radioactive decay Exam Style Questions Paper 1 CIE iGCSE Co-Ordinated Science P5.2.3 Radioactive decay Exam Style Questions Paper 1 CIE iGCSE Co-Ordinated Science Paper 1 - All Chapters Question A radioactive nucleus emits a β-particle. What happens to the proton number (atomic number) of the nucleus? A. It stays the same.B. It increases by 1.C. It decreases by 2.D. It decreases by 4. ▶️Answer/Explanation Answer: BExplanation: When a nucleus emits a β-particle (an electron), a neutron is converted into a proton, increasing the proton number by 1. Question The nucleus of an atom emits an $\alpha$-particle.How do the number of protons and the number of neutrons in the nucleus change? ▶️Answer/Explanation Ans: A More CIE iGCSE Co-Ordinated Science Paper 1 Questions..