Radioactivity
process by which some atoms emit energy and particles
Isotope
Same number of protons but different mass numbers
different number of neutrons
Nuclide
any atom characterized by an atomic number and a mass number
Alpha Particle
slow moving, 2 protons 2 neutrons (He),
Beta Particle
B symbol, fast-moving (90% speed of light). Involves a neutron converting to a proton. No mass
Gamma Rays
Y symbol, most energetic part, not considered matter
Positron
Proton converts to neutron, Beta Particle
Ionizing radiation
collective name for alpha, beta, gamma radiation. leaves a trail of ions throughout the material it penetrates
Nuclear Equation
can be used to represent the process of radioactive decay a nuclide breaks down, producing a new nuclide, smaller particles , and/or energy
m represents?
metastable isotope, meaning that it is unstable and increases its stability through gamma decay without change to mass or charge of the isotope
Binding energy
measure of nuclear stability of the nucleus
Half-life
is the time required for one-half of a given quantity of a substance to undergo change
Radiocarbon dating
estimation of the age of objects through measurement of isotopic ratios of carbon
Nuclear reactor
heat energy converted to liquid water into steam, which produces electricity
Fission
occurs when a heavy nuclear particle is split into smaller nuclei by a smaller nuclear particle
Chain reaction
when neutrons create a chain reaction
Fusion
(meaning to join together) results from the combination fo two small nuclei to form a larger nucleus with the concurrent release of large amounts of energy
Breeder reactor
variation of a fission reactor that literally manufactures its own fuel
Nuclear medicine
use of radiation in the treatment of various forms of cancer, as well as diagnosing diseases/cancers/etc..
Nuclear imaging
medical techniques involving tracers
Tracers
small amounts of radioactive substances used as probes to study internal organs
Natural radioactivity
naturally occurring
ficial radioactivity
non-radioactive nucleus is made radioactive
Background Radiation
level of radiation attributable to our surroundings on a day-to-day basis
Shielding
a way to protect from harmful radiation
Curie
measure of the amount of radioactivity in a radioactive source
roentgen
measure of very high energy ionizing radiation (x-ray & gamma) only
Rad
radiation absorbed dosage, provides more meaningful information than either of the previous units of measure
Rem
describes the biological damage caused by the absorption of different kinds of radiation of the human body
Lethal dose (LD50)
is defined as the acute dosage of radiation that would be fatal for 50% of the exposed population within 30 days.
Stability of an isotope
- Ratio of neutrons to protons
– Nuclei with large number of protons (84 or more) tend to be unstable
– The “magic numbers” of 2, 8, 20, 50, 82, or 126 help
determine stability these numbers of protons or neutrons are stable
– Even numbers of protons or neutrons are generally
more stable than those with odd numbers
– All isotopes (except 1 H) with more protons than neutrons are unstable