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14 terms

LC Chem 1.3 Radioactivity

chemistry
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Radioactivity
The spontaneous breaking up of certain unstable nuclei, accompanied by the emission of one or more types radiation.
Becquerel
Scientist who discovered radiation from uranium salts
Marie and Pierre Curie
Scientists who researched radioactivity and discovered polonium and radium
Alpha particles
Made of 2 protons + 2 neutrons (helium nuclei) with a positive charge. Little penetrating ability (stopped by a sheet of paper)
Alpha decay
When an isotope undergoes this, its atomic number decreases by 2, while its mass number decreases by 4.
Americum-241
Alpha emitter used in smoke detectors
Beta particles
Electrons with a negative charge, formed when a neutron decays into a proton and an electron. Medium penetrating ability (stopped by 5mm of aluminium)
Beta decay
When an isotope undergoes this, its atomic number increases by 1, while its mass number remains unchanged.
Carbon-14
Beta emitter used in to date archaeological artefacts
Gamma rays
High energy electromagnetic radiation which are not deflected by magnetic or electric fields, High penetrating ability (only stopped by several cms of lead)
Cobalt-60
Gamma emitter used to treat cancer or in food preservation as it kills disease causing organisms by irradiation
Radioisotope
An atom with an unstable nucleus (radionuclide).
Half-life
The time taken for half of the atoms in a sample of the radioactive isotope to decay.
Background radiation
The low level of radiation that surrounds us at all times. 90% comes from natural sources such as Radon gas