Final answer:
Measuring the percentages of stable and unstable isotopes is essential in the study of radioactivity and radioactive decay, which are important in fields like archaeology for carbon dating.
Step-by-step explanation:
Measuring the percentages of stable and unstable isotopes is a key part of the study of radioactivity and the process known as radioactive decay. Atoms acquire stability by having a certain ratio of neutrons to protons in their nucleus; those with an incorrect ratio are unstable, or radioactive, and will decay over time. For instance, while carbon-14 is a radioactive isotope (radioisotope) of carbon, carbon-12 and carbon-13 are stable isotopes. The process of measuring the activity of isotopes is crucial for various applications, including scientific research, medicine, and archaeology, particularly carbon dating where scientists calculate the age of an organic specimen by measuring the amount of carbon-14 it contains compared to stable isotopes.