The half-life of a radioactive isotope is the time it takes for a quantity of the isotope to be reduced to half its initial mass. Starting with 210 grams of a radioactive isotope, how much will be left after 3 half-lives? Use the calculator provided and round your answer to the nearest gram.

After the first half-life, you'll have 105 grams left. After the second half-life, it reduces to 52.5 grams. Finally, after the third half-life, you're left with approximately 26.25 grams, which rounds to about 26 grams. So, starting with 210 grams and going through three half-lives, you'll end up with 26 grams of the radioactive isotope! Radon-222, a well-known radioactive isotope, exemplifies this concept beautifully. With a half-life of just 3.8 days, it undergoes decay relatively quickly, which is why it’s a key player in the discussion about indoor air quality and safe living environments. Understanding half-lives helps us appreciate not only the fascinating world of radioactivity but also its implications for health and safety regulations!