11 Particle Physics (AS)

11.1 Atoms, nuclei, and radiation:

• The α-particle scattering experiment provided evidence for the existence and small size of the nucleus within an atom.
• The nuclear atom model includes protons, neutrons, and orbital electrons.
• Nucleon number (A) represents the total number of protons and neutrons in the nucleus, while proton number (Z) represents the number of protons.
• Isotopes are different forms of the same element with different numbers of neutrons in their nuclei.
• Nuclides are represented using the notation A ZX, where A is the nucleon number and Z is the proton number.
• Nucleon number and charge are conserved in nuclear processes.
• α-particles, β-particles (both β- and β+), and γ-radiation have distinct compositions, masses, and charges.
• Antiparticles have the same mass as their corresponding particles but have opposite charge.
• β– decay produces (electron) antineutrinos, while β+ decay produces (electron) neutrinos.
• α-particles have discrete energies, while β-particles have a continuous range of energies due to the emission of (anti)neutrinos.
• Radioactive decay equations represent α- and β-decay processes.

11.2 Fundamental particles:

• Quarks are fundamental particles, and there are six flavors: up, down, strange, charm, top, and bottom.
• Each flavor of quark has a specific charge, and its respective antiquark has the opposite charge.
• Protons and neutrons are composed of quarks and are not fundamental particles themselves.
• Hadrons are particles made up of quarks and antiquarks. Baryons consist of three quarks, while mesons consist of one quark and one antiquark.
• During β– and β+ decay, there are changes in the quark composition of particles.
• Electrons and neutrinos are fundamental particles known as leptons.