Which of these is a characteristic of radioisotopes?

The characteristic that radioisotopes spontaneously break down into products is correct because radioisotopes are unstable forms of elements that undergo radioactive decay. This process involves the release of energy in the form of radiation, including alpha particles, beta particles, or gamma rays, as they transform into more stable isotopes or different elements altogether. This inherent instability is the defining feature of radioisotopes, making them valuable in various applications, such as medical diagnostics and treatments, as well as in dating techniques like carbon dating.

The other choices reflect misconceptions about radioisotopes. For instance, while some isotopes are stable, radioisotopes are specifically defined by their instability and propensity to decay. Additionally, many radioisotopes have well-characterized decay products, which can be essential in tracing the progression of radioactive decay. Finally, radioisotopes are extensively used in dating, particularly in archaeology and geology, to estimate the age of organic materials or geological formations based on the known rates of decay.