If we use uranium-238 as our starter isotope, what happens is that a nuclear decay event happens (in this case an alpha decay) and the U-238 transforms into a daughter isotope thorium (Th-234). The half-life of this transition is 4.5 billion years. Thorium-234 then undergoes a decay. And the process continues until a stable isotope is created as the last daughter of a decay chain. Note that there will be different half lives for the transition events, and the modes of decay will vary depending on what daughter is now the parent in the next decay event. Use the link below to see all the steps. The chart will show the whole chain including the half-life of isotope undergoing decay, the decay mode, and the daughter. Follow along using the keys and the process will reveal itself.