IGCSE›Cambridge IGCSE Physics›Mind mapsThe NucleusCambridge IGCSE Physics: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsParticlesProton: relative charge +1, in nucleusNeutron: charge 0, in nucleusElectron: charge −1, orbits nucleusNeutral atom: protons = electronsAlpha scatteringMost alpha particles pass straight through→ atom is mostly empty spaceA few deflected large angles→ nucleus small, dense, positiveNumbersProton number Z = protonsNucleon number A = protons + neutronsNeutrons = A−ZA - ZA−ZNuclide notation ZAX^A_Z XZAXThe nucleusprotons and neutronsZAX^A_Z XZAXp⁺nIsotopesSame proton number, different neutronsDifferent nucleon numberCarbon-12 and carbon-14 both have 6 protonsCarbon-12 has 6 neutrons, carbon-14 has 8Fission and fusionFission: large nucleus splits into smaller nucleiFusion: two small nuclei join into a larger oneShown with nuclide equationsIonsLose electrons → positive ionGain electrons → negative ion