The parent nuclide undergoes two successive -decays followed by one -decay. Determine the atomic num — Nuclear Chemistry and Radioactivity Chemistry Question

💡 Solution & Explanation

Two $\beta^-$ -decays increase $Z$ by 2 ($90 \rightarrow 92$), keeping $A$ at 234, forming ${}_{92}^{234}U$. One subsequent $\alpha$ -decay decreases $Z$ by 2 ($92 \rightarrow 90$) and decreases $A$ by 4 ($234 \rightarrow 230$), yielding ${}_{90}^{230}Th$.