Final answer:
During radioactive decay, atoms change into a different, more stable element. This process is known as transmutation and is measured by half-life, which is the time required for half of the radioactive atoms to decay.
Step-by-step explanation:
During radioactive decay, atoms of one element break down into another, more stable element. Radioactive decay describes the loss of energy and/or mass when an unstable atom's nucleus releases radiation. Through this process, known as transmutation, the atom is converted to a new element. Radioactive decay is exponential in nature, and its rate is often expressed in terms of half-life, the time required for half of the radioactive atoms to decay. Substances undergo a radioactive decay series, proceeding through multiple decays before ending in a stable isotope. Each radioisotope has a characteristic half-life, which is constant and unaffected by environmental conditions.