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title: "A radioactive nucleus in state 1 with atomic number \\(Z = 92\\) and mass number \\(A = 238\\) undergoes Transition 1 to state 2 (\\(Z = 90\\), \\(A = 234\\)), and then Transition 2 to state 3 (\\(Z = 91\\), \\(A = 234\\)), as represented in the graph of mass number \\(A\\) versus atomic number \\(Z\\). Which of the following correctly identifies the decay process occurring in Transition 1 and compares the magnitude of the change in mass number \\(|\\Delta A|\\) for Transition 1 to that for Transition 2?"
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url: "https://nerd-notes.com/ubq/117415/"
date_modified: "2026-08-04T06:52:05+00:00"
---

# A radioactive nucleus in state 1 with atomic number \(Z = 92\) and mass number \(A = 238\) undergoes Transition 1 to state 2 (\(Z = 90\), \(A = 234\)), and then Transition 2 to state 3 (\(Z = 91\), \(A = 234\)), as represented in the graph of mass number \(A\) versus atomic number \(Z\). Which of the following correctly identifies the decay process occurring in Transition 1 and compares the magnitude of the change in mass number \(|\Delta A|\) for Transition 1 to that for Transition 2?

A radioactive nucleus in state 1 with atomic number \(Z = 92\) and mass number \(A = 238\) undergoes Transition 1 to state 2 (\(Z = 90\), \(A = 234\)), and then Transition 2 to state 3 (\(Z = 91\), \(A = 234\)), as represented in the graph of mass number \(A\) versus atomic number \(Z\). Which of the following correctly identifies the decay process occurring in Transition 1 and compares the magnitude of the change in mass number \(|\Delta A|\) for Transition 1 to that for Transition 2?

![A line graph plotting Mass Number A on the vertical axis against Atomic Number Z on the horizontal axis. The vertical axis ranges from 232 to 240 with tick marks labeled 232, 234, 236, 238, 240. The horizontal axis ranges from 89 to 93 with tick marks labeled 89, 90, 91, 92, 93. State 1 is marked with a filled circle at Z = 92, A = 238. A solid arrow labeled 'Transition 1' points from State 1 down and left to State 2 at Z = 90, A = 234. A solid arrow labeled 'Transition 2' points from State 2 up and right to State 3 at Z = 91, A = 234. State 2 and State 3 are each marked with filled circles. No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1785826325-34VBDz.jpg)

- **A.** Process: Beta-minus decay; Mass number change: \(|\Delta A_1| = |\Delta A_2|\)
- **B.** Process: Beta-minus decay; Mass number change: \(|\Delta A_1| > |\Delta A_2|\)
- **C.** Process: Alpha decay; Mass number change: \(|\Delta A_1| > |\Delta A_2|\)
- **D.** Process: Alpha decay; Mass number change: \(|\Delta A_1| < |\Delta A_2|\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/117415/*