Nuclear Stability Relative Stability of Different Nuclei Two Methods Which isotopes? Binding Energy What holds an atom together? Forces of Nature and Atomic Structure: Band (Island) of Stability N/Z ratio Number of stable isotopes Isotope trends among the elements: Binding Energy, but first Comparing stability: O-O single bond strength = 146 kJ/mol O=O double bond strength = 496 kJ/mol Which is more stable, O 2 or O 3 ? O 2 : O=O O 3 : O=O-O Predict what you think the trend will be: As atomic number increases, what will happen to stability? Split up class and do: Do all isotopes using Excel Isotopedata_stable.xls Modes of Radioactive Decay U-238 Decay SeriesAnd the problem with radon. Decay modes and the island of stability.