A decay series is a sequence of radioactive decay processes that occur when an unstable atomic nucleus transforms into a more stable form. This process involves the emission of particles and energy, leading to the formation of different isotopes until a stable isotope is reached. Each step in the series is characterized by a specific half-life, which is the time it takes for half of the radioactive material to decay. In a typical decay series, a parent isotope decays into a daughter isotope, which may also be unstable and continue to decay. For example, the decay series of uranium-238 eventually leads to the stable isotope lead-206. Understanding decay series is important in fields like nuclear physics and radiometric dating.