Chapter 41: Heavy Elements and Radioactivity

Beyond iron, fusion stops giving energy. Heavy elements form by neutron capture—slow (s-process) in AGB stars, rapid (r-process) in supernovae and neutron star mergers. Unstable nuclei then transform via three decay channels—α, β, γ—each restoring T² saturation balance. This chapter traces the formation of gold, lead, and uranium, classifies radioactive decay from the τ³ perspective, and shows how abundance peaks at magic neutron numbers provide direct evidence for T² shell structure.