Question

what occurs during one half-life?
○ half of a daughter isotope undergoes radioactive decay to form a parent isotope.
○ half of a parent isotope undergoes radioactive decay to form a daughter isotope.
○ all of a daughter isotope undergoes radioactive decay to form a parent isotope.
○ all of a parent isotope undergoes radioactive decay to form a daughter isotope.

Explanation:

To determine the correct answer, we recall the concept of half - life in radioactive decay. The parent isotope is the unstable isotope that undergoes decay, and the daughter isotope is the product of that decay. In one half - life, half of the parent isotope (the unstable one) will decay to form the daughter isotope (the stable or less - unstable product).

• The first option is incorrect because daughter isotopes are the products of decay, not the ones that decay to form parent isotopes.
• The third option is incorrect as daughter isotopes do not decay to form parent isotopes, and also, it says "all" which is not in line with the half - life concept.
• The fourth option is incorrect because in one half - life, only half of the parent isotope decays, not all of it.

Answer:

B. Half of a parent isotope undergoes radioactive decay to form a daughter isotope.