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GCSE Physics · key term
A particle made of two protons and two neutrons; it is a helium nucleus.
Used by AQA, Edexcel and OCR
Specification 4.4.2.1, 4.4.2.2 · Paper 1
A particle consisting of two protons and two neutrons, identical to a helium nucleus.
A particle consisting of two protons and two neutrons, represented as or .
Specification 6.10, 6.15, 6.17 · Paper 1
A particle consisting of two protons and two neutrons, identical to a helium nucleus.
A particle equivalent to a helium nucleus, containing two protons and two neutrons but no electrons.
A positively charged particle made of two protons and two neutrons.
Specification P1.1a, P6.1d, P6.1e, P6.1f, P6.1l · Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
A positively charged particle used to probe atoms in the gold-foil experiment.
Revise: Development of the atomic modelIn the 1909 gold-foil experiment, his colleagues Hans Geiger and Ernest Marsden directed positively charged alpha particles at very thin gold foil. A surrounding fluorescent screen flashed where particles struck it, allowing them to record the directions in which particles emerged.
A particle made of two protons and two neutrons, identical to a helium nucleus.
A helium nucleus containing two protons and two neutrons, represented by or .
A particle made of two protons and two neutrons, emitted by some unstable nuclei.
Paper 1, Paper 2
A particle made of two protons and two neutrons, with mass number 4 and charge .
Revise: Isotopes and Radioactive EmissionsThe OCR specification includes four possible emissions: alpha particles, beta particles, neutrons and gamma rays. Each carries a characteristic mass number and charge, so each affects the nucleus differently.
Do not describe an alpha particle as a helium atom: a neutral helium atom also has two electrons, whereas an alpha particle has none.
An alpha particle may be written as or ; recognise both notations.
Give the order of penetration explicitly: gamma rays are most penetrating, then beta particles, then alpha particles.
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