Nuclear Physics and Radioactivity Vocabulary

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proton
the nucleus of the simplest atom- hydrogen. It has a positive charge of +q and a mass of m=1.67×10^-27 kg
neutron
a particle found in the nucleus that is electrically neutral and that has a mass almost identical to the proton. It was discovered in 1932 by James Chadwick, Its charge is q=0, its mass is m=1.6749×10^-27 kg, (Chadwick’s discovery established that the nucleus contained two types of particles)
nucleons
term that refers to the two constituent particles of a nucleus
atomic number
the number of protons in a nucleus (designated by the letter Z)
atomic binding energy
the total number of protons and neutrons (designated by the letter A)
nucleon
the mass of a nucleus is very close to Z times the mass of one ___
isotope
nuclei that contain the same number of protons but different numbers of neutrons; are generally described as
“element-#”
mass defect
th difference in the mass of a nucleus and the sum of the masses of its constituent particles
nuclear binding energy
the amount of energy that must be put into a nucleus to break it into its constituent particles; it is the energy equivalent of the mass defect found by using E=mc^2.
strong nuclear force
an attractive force that acts between all nucleons; protons attract each other via this force while they repel each other via the electric force.
radioactive
nuclei that decay, emitting radiation, are considered to be this. in other words a nucleus that is coming apart is doing this. a new element is produced
transmutation
the changing of one element into another element via radioactive decay.
~conservation of energy
~conservation of electric charge
~conservation of mass
when unstable nuclei disintegrate, they must obey what three laws of physics?
alpha particle
has a charge of q=+2 and a mass of A=4, when this is emitted the number of protons is reduced by two and its mass is reduced by four. these are emitted by very large nuclei where the strong nuclear force is insufficient to hold the nuclei together
helium
an alpha particle is essentially a ___ nucleus
beta particle
a negative electron emitted from he nucleus that came from a broken down neuron. are emitted by nuclei that have too many neutrons relative to the number of protons
weak nuclear force
involved in the production of a beta particle in the nucleus
gamma radiation
is composed of high energy photons, has no charge and no mass
positron
a positive electron produced in the nucleus by the decay of a proton into a positron and a neuron. it has a charge of q=+1 and essentially no mass. there are emitted by nuclei that have too few neutrons relative to their number of protons
protron
the nucleus of a hydrogen atom. they symbol is p
proportionality
the decay constant is a constant of ____
half life
the time it takes for half he original amount of a substance to decay
mass-energy equivalence
one of the most profound results of Einstein’s theory of relativity was the fact that mass could be converted into energy and vice versa. (E=mc^2)
fission
a division of a nucleus into two or more smaller daughter nuclei.
chain reaction
neutrons produced by the fission of one nucleus induce the fission of there nuclei
critical mass
he minimum mass of uranium needed to produce a self-susaining chain reaction
fusion
two or more nuclei combine to form a larger nucleus. (sun)
artificial transmutation
process of using nuclear reactions to change the atomic number of the nucleus by changing one element into another
moderator
slows down neutrons produced in chain reactions so the can be more easily absorbed by other nuclei so fission continues
control rods
absorb neutrons, controlling the rate of reaction
breeder reactors
ones in which some of the neutrons produced in the fission of uranium produce plutonium. this plutonium can be used in an atomic bomb.
Categories: Atomic Physics