Question

an article about half-lives describes a parent isotope. what is a parent isotope?
○ the isotope that forms from the radioactive decay of a less stable isotope
○ the isotope that forms from the radioactive decay of a more stable isotope
○ an isotope that undergoes radioactive decay to form a less stable isotope
○ an isotope that undergoes radioactive decay to form a more stable isotope

Explanation:

To determine the correct definition of a parent isotope, we analyze each option:

• The first two options describe a daughter isotope (formed from decay), so they are incorrect.
• Radioactive decay aims for greater stability, so a parent isotope decays to form a more stable isotope (not less stable, eliminating the third option).
• The fourth option matches: a parent isotope undergoes radioactive decay to produce a more stable isotope (daughter isotope).

Answer:

D. an isotope that undergoes radioactive decay to form a more stable isotope