Question

Which one of these is the heaviest known stable nuclide?

• A. $P{b}^{208}$
• B. $P{b}^{206}$
• C. $P{b}^{210}$
• D. $P{b}^{204}$

Answer 1

The correct option is A $P{b}^{208}$

Lead's four stable isotopes each have 82 protons, a magic number in the nuclear shell model of atomic nuclei. The isotope lead-208 also has 126 neutrons, another magic number, and is hence double magic, a property that grants it enhanced stability: lead-208 is the heaviest known stable nuclide.