Final answer:
Radioactive decay occurs when an unstable isotope emits radiation to transform into a more stable nuclide. This process releases energy, and possibly mass, and it involves various types of emissions such as alpha, beta, and gamma decay. Each isotope has a specific half-life, the period needed for half of the isotope's atoms to decay.
Step-by-step explanation:
During radioactive decay, an unstable isotope, also known as a radioisotope, changes spontaneously into another nuclide. This process occurs because the nuclei that are not within the band of stability are unstable and tend to achieve a more stable state. The transformation involves the release of energy and sometimes mass, as the atom's nucleus emits radiation to become more stable.
There are various types of radioactive decay, such as alpha, beta, and gamma decay. Each of these changes the composition of the original nucleus, known as the parent nuclide, resulting in a daughter nuclide. The daughter nuclide could be stable or might further decay if it is still outside the band of stability. An example of this decay process is Carbon-14, which decays into Nitrogen-14, a stable product.
In nuclear reactions, significant amounts of energy are released, which are much greater than the energies involved in chemical reactions. Furthermore, nuclear reactions, and thus radioactive decay, occur regardless of environmental conditions such as temperature and pressure. Each radioisotope has a characteristic half-life, the time required for half of its atoms to decay.