radioactivity
the process by which materials give off rays emitted by uranium atoms
radiation
the penetrating rays and particles emitted by a radioactive source
radioisotopes
the nuclei of unstable isotopes
alpha particle
particle emitted by a radioactive source that contains two protons and two neutrons, and has a double positive charge
beta particle
an electron resulting from the breaking apart of a neutron in an atom
gamma ray
a high-energy photon emitted by a radioisotope
nuclear force
an attractive force that acts between all nuclear particles that are extremely close together
band of stability
the location of stable nuclei on a neutron-proton plot
positron
a particle with the mass of an electron but a positive charge
half-life
the time required for one-half of the nuclei of a radioisotope to decay to products
transmutation
the conversion of an atom of one element to an atom of another element
transuranium elements
all the elements in the periodic table with atomic numbers above 92 and Technetium (43) and Promethium (61)
fission
the splitting of a nucleus in to smaller fragments
neutron moderation
process that slows down neutrons so the reactor fuel (uranium) captures them to continue the chain reaction
neutron absorbtion
process that decreases the number of slow-moving electrons
fusion
occurs when nuclei combine to form a nucleus of greater mass
ionizing radiation
radiation with enough energy to knock electrons off some atoms of the bombarded substance to produce ions
Geiger counter
uses gas filled metal tube to detect radiation
scintillation counter
uses a phospher-coated surface to detect radiation
film badge
consists of several layers of photographic film covered with black lightproof paper, all encased in a plastic or metal holder; used as a radiation detector
neutron activationanalysis
a procedure used to detect trace amounts of elements in samples
radioactive dating
carbon-14 and its half-lives can be used to date rock layers
chain reaction
a continuing series of fission reactions in which split neutrons split other neutrons
t1/2 represents:
half life
What is an alpha particle made of?
two protons and two neutrons forming a helium nuclei
What kind of rays have the most penetrating power?
gamma rays
Beta particles are...
electrons
What can shield gamma rays?
lead and concrete
Who coined the term "radioactivity"?
Becquerel
unstable nuclei are...
radioisotopes
What are gamma rays?
electromagnetic radiation
What can shield Alpha decay?
cloth or paper
When is Alpha radiation dangerous?
when ingested or eaten
half-life
the time for half the mass of a sample to radioactively decay
Why is nuclear fusion not practiced?
extremely high temperatures are needed