Some atomic nuclei are unstable — they have the wrong balance of protons and neutrons, or simply too much energy. These nuclei will spontaneously "decay" by emitting particles or energy to become more stable. You can't predict WHEN a specific nucleus will decay (it's completely random!), but you can predict how many from a large sample will decay. This is radioactivity — discovered accidentally by Henri Becquerel in 1896 when uranium fogged his photographic plates!
This introduction covers Unstable Nuclei 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 1 of 14 in this topic. Use this introduction to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Radioactive Decay
An alpha particle consists of which particles?
Explain why alpha radiation is described as highly ionising but weakly penetrating.
Quick recall flashcards
Beta particle is?
Fast electron from nucleus
Alpha particle is?
2p + 2n (helium nucleus)