Radon isotopes are variations of the element radon, which is a colorless, odorless gas that occurs naturally in the environment. The most common isotopes of radon are radon-222, radon-220, and radon-219. These isotopes differ in the number of neutrons in their nuclei, affecting their stability and radioactive properties. Radon-222 is the most prevalent and is produced from the decay of uranium and thorium in soil and rock. It has a half-life of about 3.8 days, making it a significant concern for indoor air quality, as it can accumulate in homes and pose health risks, including lung cancer.