An atomic nucleus A is composed of 84 protons and 128 neutrons. The nucleus A emits an α-particle and is transformed into a nucleus B. What is the composition of B?
Answer & explanation
Correct answer: option 2
α-particle is helium with A = 4 and Z = 2. Nucleus B has 128-2 = 126 nuetrons and 84-2 = 82 protons.