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21 Cards in this Set

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Radioactivity was discovered by
Henri Becquerel
the breakdown of an unstable atomic nucleas with the release of particles and rays
Radioactivity
Pierre and Marie Curie discovered what 2 new elements?
Polonium and Radium
has the highest atomic weight in group 2; the least electronegative and the most metallic of its group
Radium
1) affects the light-sensitive emusion on a photographic film
2) produces an electric charge in the surrounding air
3) produce a fluorescence with certain other compounds
4) their radiations have special physiological effects
5) they undergo radioactive decay
Radioactive properties
the length of time during which half of a given number of atoms of a radioactive nuclide decays
Half-life
helium nuclei that have been emitted from a radioactive source; contains 2 protons and 2 neutrons and have a double positive charge
Alpha
don't travel very far and are not very penetrating; they are stopped by a sheet of paper or a leyer of skin
Alpha
fast moving electrons formed by the decomposition of a neutron; breaks down into a proton and electron
Beta
much smaller than alpha particles and have half as much charge; much more penetrating but can be stopped by aluminum foil or thin pieces of wood
Beta
electromagnetic radiation; emitted along with alpha or beta radiation
Gamma
have no mass and no electrical charge, so it does not alter the atomic number or mass number; passes through paper, wood, and the human body; can be stopped by several feet of concrete, or several inches of lead
Gamma
the conversion of an atom of another element
Transmutation
elements in the periodic table with atomic numbers above 92
Transuransim Elements
the splitting of the nucleus into smaller fragments
Fission
when 2 nuclei combine to produce a nucleus of heavier mass
Fusion
a gas-filled metal tube to detect radiation; used to detect beta only
Geiger Counter
uses a phosphor to detect ragiation; can detect all types of radiation
Scintillation Counter
several layers of photographic film covered with black light proof paper encased in a plastic or metal holder; can detect all types
Film Badge
Uses of radioisotopes
1) Trace fertilizers and herbicides
2) Diagnose diseases
3) Treat cancer
4) Detect gunpowder
5) Detect art forgeries
a particle with the mass of an electron but a positive charge
Positron