PhysicsCode 9702
Atoms, nuclei and radiation
What this topic asks you to be able to do
- infer, using the outcomes of the α-particle scattering experiment, that the nucleus is present and of small size
- describe a basic model of the nuclear atom, with protons, neutrons and orbital electrons as its parts
- distinguish proton number from nucleon number
- understand that isotopes are variants of a single element that differ in how many neutrons their nuclei contain
- understand and apply the A/Z X notation when representing nuclides
- understand that every nuclear process conserves both nucleon number and charge
- outline the mass, charge and composition of α-, β- and γ-radiations, with both β– (electrons) and β+ (positrons) included
- understand that the antiparticle of a given particle matches it in mass yet carries the reverse charge, and that the antiparticle of an electron is the positron
- state that in β– decay an (electron) antineutrino is produced, and in β+ decay an (electron) neutrino
- understand that α-particles have discrete energies, whereas the energies of β-particles cover a continuous range, since β-decay also emits (anti)neutrinos
- represent α- and β-decay by writing radioactive decay equations like UTh 92 238 90 234 2 " + 4α
- use the unified atomic mass unit (u) to express masses