What is the half-life of radon-220?

• A. 24 hours
• B. 55.6 seconds
• C. 1620 years
• D. 3.8 days

Answer: (B)

Verified step by step guidance

1. Understand that the half-life of a radioactive isotope is the time required for half of the radioactive nuclei in a sample to decay.
2. Identify the isotope in question, which is radon-220, also known as thoron, and recall or look up its known half-life value from reliable sources or tables.
3. Note that the half-life of radon-220 is very short compared to other isotopes, typically measured in seconds rather than hours or years.
4. Compare the given options (24 hours, 55.6 seconds, 1620 years, 3.8 days) with the known half-life of radon-220 to select the correct one.
5. Confirm that the half-life of radon-220 is approximately 55.6 seconds, which matches the known scientific data.