Illinois Home Inspector Practice Exam

What happens to the decay of radon progeny over time?

1. It accelerates indefinitely

2. Stable, non-radioactive progeny are formed

3. It turns into a gas

4. It stops after five days

The correct answer is: Stable, non-radioactive progeny are formed

The decay of radon progeny over time results in the formation of stable, non-radioactive progeny. Radon itself is a radioactive gas, and as it decays, it transforms into a series of daughter isotopes, often termed progeny. These progeny can also be radioactive, but they will eventually decay into stable isotopes, meaning that after succeeding decay steps, the progeny reach a point where they are no longer radioactive. This is a natural aspect of radioactive decay chains. The other options do not accurately reflect the behavior of radon progeny. The decay does not accelerate indefinitely, as it follows a predictable pattern described by its half-lives. It also does not turn into a gas; rather, the progeny are typically solid or particulate matter. While some progeny have short half-lives and might be more prevalent shortly after radon is released, the decay process does not simply stop after five days, as the decay chain continues until stable isotopes are formed.