A nucleus of the stable isotope Pb(208,82) has more neutrons than protons. Explain why there is this imbalance between proton and neutron numbers by referring to the forces that operate within the nucleus.

Must include 3 points from 1-5 and 1 point from 6-7 for 4 marks.1.Strong nuclear force (SNF) affects nucleons or protons and neutrons.2. SNF attraction extends up to 3 fm (allow 1–4 fm) 3. The SNF is repulsive below about 0.8 fm (allow 0.3 to 1 fm and prevents the nucleus totally collapsing) 4. Electromagnetic/electrostatic repulsive force (only) acts between protons 5. EM forces are long range/infinite/acts across whole nucleus/acts on all protons(so increases as proton number increases)6. More neutrons are needed to hold nucleus together / add to binding force/increase instability/reduce stability 7. Fewer protons are required so as to reduce the repulsion/reduce instability/increase stabilityProcess of answering: