This how it works covers How It Works: The Mechanism of Each Decay within Radioactive Decay for GCSE Physics. Revise Radioactive Decay in Atomic Structure for GCSE Physics with 15 exam-style questions and 6 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 6 of 14 in this topic. Use this how it works to connect the idea to the wider topic before moving on to questions and flashcards.
⚙️ How It Works: The Mechanism of Each Decay
Alpha decay occurs in very large, heavy nuclei (like uranium). The nucleus is so large that the strong nuclear force cannot hold it together effectively. Emitting an alpha particle (helium-4 nucleus) reduces the size of the nucleus significantly, making the remaining nucleus more stable.
Beta decay occurs when a nucleus has too many neutrons relative to its protons. A neutron is converted into a proton via the weak nuclear force interaction: n → p + e⁻ + antineutrino. The emitted electron (beta particle) and an antineutrino carry away the excess energy.
Gamma emission occurs when a nucleus is in an excited energy state after alpha or beta decay. The nucleus releases this excess energy as a high-energy photon (gamma ray). No change in nucleon numbers occurs — the nucleus simply loses energy and drops to a lower energy state.
Practice questions for Radioactive Decay
An alpha particle consists of which particles?
Explain why alpha radiation is described as highly ionising but weakly penetrating.