Figure 6 shows the mass number and the atomic number for the nuclei of five different atoms - AQA - GCSE Physics - Question 6 - 2021 - Paper 1

The two atoms in Figure 6 that are the same element are D and E. This is determined by their matching atomic numbers, indicating that they are isotopes of the same element.

To indicate the alpha decay of nucleus B, draw a downward arrow from the B nucleus in Figure 7, pointing to a new nucleus with a mass number of 228 (2 deducted from mass number) and an atomic number of 86 (2 deducted from atomic number). The new nucleus represents the element with atomic number 86.

The ‘random nature of radioactive decay’ refers to the inherent unpredictability in the timing of when a particular nucleus will decay. Although the decay series can be statistically modeled over a large number of atoms, it is impossible to predict the exact moment a single atom will decay.

The decay process begins with a polonium (Po) nucleus emitting an alpha particle, resulting in the formation of a lead (Pb) nucleus. The lead nucleus then undergoes a beta decay, emitting a beta particle and producing a bismuth (Bi) nucleus. Finally, the bismuth nucleus also undergoes a beta decay, resulting back to a polonium (Po) nucleus. Thus, through these successive decays involving different particles, the original element is reformed.