When uranium-238 emits an alpha particle, it becomes thorium-234,which emits a beta particle to become protactinium. What is the atomic number of protactinium?
Correct answer: B. 91
- A. 90
- B. 91
- C. 89
- D. 92
Explanation
An α-particle decreases the atomic number bt 2 and mass number by 4. And β-particle emission increases the atomic number by 1.
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About Radioactive Decay
Radioactive decay is the spontaneous transformation of unstable nuclei, described by decay constant, activity, half life and the exponential decay law. Work includes alpha, beta and gamma emissions, decay equations and remaining nuclei, with half life distinguished from the time required for complete decay.
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