radioactivity the process by which nuclei emit particles and rays these penetrating particles and...
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RadioactivityThe process by which nuclei emit particles and raysThese penetrating particles and rays are called radiation.
Types of RadiationAlpha particle-two p+ and two n0 (helium nucleus)Changes identity of the atom (drops by two atomic #s)Little penetrating power (stopped by paper or skin)
Types of RadiationBeta particle- a high speed e-Comes from a neutron that breaks apartChanges identity of the atom (up one atomic #)Stopped by Al foil or woodSymbol is -1e or -1
Types of RadiationGamma RadiationHigh-energy photon emitted as a gamma rayOften emitted along with or radiationDoes not change identity of the isotopeHighly penetrating and very dangerous to humans
Radioactive Decay as EquationsThe symbols for the various particles are shown:
When a radioisotope changes identity, this is called a transmutation reaction.
Half-LifeEvery radioisotope has its own rate of decay measured by its half-life.Half-life (t) is the time required for half the nuclei of that radioisotope to decayCould be a fraction of a second or billions of years.
FissionWhen nuclei of some isotopes are hit with neutrons, they split into smaller fragments. This is fission.Every time an isotope splits, TREMENDOUS amounts of energy are released.
Fission Chain ReactionIn a chain reaction, the neutrons produced strike other atoms, which produce more neutrons, etc.This is how a nuclear bomb works.It is also how reactors work, but with controls.
Nuclear ReactorsMake use of the energy produced by fission.
Nuclear ReactorsThe fuel rods from reactors, when spent, are a major waste issue.They are stored indefinitely, or shipped to another location.They wont be safe until the isotopes are stable, which depends on the half-life of the isotope.The next slide has some fuel rod photos.
FusionOccurs when nuclei combine to produce a heavier nucleus.Occurs naturally in the sun. (4 H nuclei become 1 He nucleus)It is how current nuclear warheads work.