P7 - Higher 0.0 / 5 ? PhysicsRadioactivityGCSEAQA Created by: ElizabethSnCreated on: 05-04-17 20:25 Alpha Radiation Alpha particles that are emitted in the type of radioactive decay (alpha decay) 1 of 24 Beta radiation Beta particles (electrons) 2 of 24 Gamma radiation Also known as gamma rays, it's the most penetrating radioactive substance 3 of 24 Unstable nucleus A nucleus that does not have enough strong nuclear forces to keep it permanently together 4 of 24 Can radioactive decay be predicted? No, as it's a random event 5 of 24 What is at the centre of every atom? A positively charged nucleus which is much smaller than the atom and which stores the biggest mass 6 of 24 What is the Plum Pudding model? A sphere of positive charge with electrons scattered around the sphere 7 of 24 Photon The radiation emitted when an electron moving around the nucleus jumps from one energy level to a lower one 8 of 24 Atomic number Number of protons in the atom 9 of 24 Mass number Number of protons plus neutrons in the atom 10 of 24 Isotope An atom of the same element with a different number of neutrons 11 of 24 Ionisation When the radiation from a radioactive substance knocks electrons out of the atom and gives the atoms a charge 12 of 24 Irradiated An object that has been exposed to ionising radiation 13 of 24 Radioactive contamination The unwanted presence of materials containing radioactive atoms of other materials. 14 of 24 What can ionisation do to a living cell? Damage or kill it 15 of 24 Activity The number of unstable atoms that decay per second in a radioactive source. 16 of 24 Count rate The number of counts per second detected by the Geiger counter. 17 of 24 Half-life of a radioactive isotope The average time it takes for the number of nuclei of the isotope in the sample to halve 18 of 24 Nuclear fission The splitting of an atom's nucleus into two smaller nuclei and the release of two or three neutrons and energy. 19 of 24 Chain reaction Reactions in which one reactions causes further reactions, which in turn cause further reactions etc 20 of 24 Nuclear fission reactor Reactors that release energy steadily due to the fission of a suitable isotope 21 of 24 Moderator Substance in a nuclear reactor that slows down fission neutrons. 22 of 24 Nuclear fusion The process of forcing the nuclei of two atoms close enough together so that they form a single larger nucleus. 23 of 24 Radon gas An alpha particle emitting isotope which can seep through houses through the ground in some areas. 24 of 24
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