Answer: Helium-4 nuclei (2 protons + 2 neutrons).
- A Electrons ejected directly from the nucleus
- B Helium-4 nuclei (2 protons + 2 neutrons)
- C High energy photons emitted from nuclear transitions
- D Free neutrons ejected from an unstable nucleus
Correct answer: B. Helium-4 nuclei (2 protons + 2 neutrons)
Explanation: Alpha particle = helium-4 nucleus (2 protons + 2 neutrons). Symbol: alpha or He-4.
Binding energy per nucleon rises sharply for light nuclei, peaks around iron-56 (the most stable nucleus), then slowly declines for heavier nuclei - which is exactly why fusing light nuclei or splitting heavy nuclei both release energy: each moves the products toward this stability peak.
Concept context
Radioactivity, nuclear reactions, fission, fusion, and binding energy.