9702 · 11.1
Atoms, nuclei and radiation — FAQ
Frequently asked questions for 9702 Atoms, nuclei and radiation. Direct answers first, then deeper explanation — then practise with marking.
Why is Rutherford's experiment so important in understanding atomic structure?
It disproved the 'plum pudding' model by showing that atoms are mostly empty space, with a tiny, dense, positively charged nucleus at their core. This completely changed our understanding of atomic architecture, forming the basis of our current model.
What's the main difference in properties between alpha and gamma radiation?
Alpha particles are relatively heavy and highly ionising but have very low penetrating power (stopped by paper). Gamma rays are high-energy photons with very low ionising ability but extremely high penetrating power (requiring thick lead or concrete to stop).
How do antiparticles relate to their corresponding particles?
An antiparticle has the exact same mass as its particle counterpart but possesses the opposite electric charge and other quantum numbers. For example, a positron () is the antiparticle of an electron ().
What is the difference between a hadron and a lepton?
Hadrons are composite particles made of quarks (e.g., protons, neutrons) and they experience the strong nuclear force. Leptons are fundamental particles (e.g., electrons, neutrinos) that do not experience the strong force.