Chapter 25 Nuclear Chemistry Test Study Guide

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Radioisotope
unstable isotope that initiate nuclear reactions. These isotopes become more stable when changes occur in their nuclei.
Radioactivity
spontaneous emission of rays or particles from certain elements such as uranium
Alpha Particle
when an atom loses an alpha particle, the atomic number of the product is lower by two and it’s mass is lower by four. Sometimes written as a helium nucleus.
Beta Particle
results from the breaking apart of a neutron in the nucleus of an atom. The neutron breaks apart into a proton which remains in the nucleus, and fast-moving electron which is ejected from the nucleus.
Gamma Ray
high energy rays with no mass and no electrical charge. Does not alter the atomic number or mass number of an atom. Dangerous!! Often emitted along with alpha and beta radiation. Gamma is not a particle but a high energy wave.
Chemical Reactions
electrons react outside the nucleus. same number and kind of atoms appear in the reactants and products. no new elements are produced.
Nuclear Reactions
protons and neutrons react inside the nucleus. elements are transmuted into other elements. reactions involve the emission of alpha, beta, and gamma from the nucleus.
Positron
particle with the same mass as an electron but with a positive charge
Transmutation
the conversion of an atom of one element into an atom of another element
Half-life
time required for one-half of the nuclei in a radioisotope sample to decay into products
Nuclear Fission
nuclei split into smaller fragments
Nuclear Fusion
when nuclei combine to produce a nucleus of greater mass
Chain Reaction
some of emitted neutrons react with other fissionable atoms, which emit neutrons that react with still more fissionable atoms
Ionizing Radiation
radiation with enough energy to knock electron off some atoms producing ions
What determines the stability of the nucleus?
stability of the nucleus depends on ratio of neutrons and protons
Where do you find radioactive elements on the periodic table?
all nuclei with an atomic number greater than 83 are radioactive
Which process produces the greatest amount of energy?
nuclear fusion
Which process occurs on the sun?
nuclear fusion
What is produced on the sun?
hydrogen nuclei fuse to make helium nuclei
What two processes control the nuclear reaction that occurs in nuclear power plants?
neutron moderation and neutron absorption
What particle triggers a chain reaction and sustains it?
neutrons that are emitted when Uranium undergoes fission
What types of devices can detect ionizing radiaiton?
Geiger counters, scintillation counters, and film badges
Categories: Nuclear Chemistry