Chapter 3: Nuclear Chemistry

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the positively charged protons and neutral neutrons contained in an atom’s densely packed nucleus
process of changing one element to another through radioactive decay
Radioactive decay
A spontaneous process in which unstable nuclei lose energy by emitting radiation
Radioactive Nuclide
an unstable nucleus that undergoes radioactive decay
Alpha emission
4/2He, mass#=-4, atomic#=-2…cannot penetrate dead skin, tissue, or paper
Beta emission
when nuclei have too many neutrons relative to protons, it emits a beta particle. it increases the number of protons and decreases the number of nuetrons…atomic number increases
Positron emission
a proton is converted to a neutron, a positron is emitted, the atomic number decreases by 1, the mass number stays the same
Electron Capture
Radioactive process in which a nucleus captures an inner-shell electron that combines with a proton to form a neutron. As a result, the atomic number decreases by 1, but the atomic mass remains the same.
Gamma emission
emits a very high energy photon. This is due to the nucleus reorganizing itself in a lower energy state, much like a photon is given off by an electron when it moves from a high energy level to a lower one. The nucleus does not change otherwise.
the time required for one half of the atoms of a radioisotope to emit radiation an decay products
Artificial transmutation
the transformation of atoms of one element into atoms of another element as a result of a nuclear reaction, such as bombardment with neutrons
particle accelerator
A machine that moves atomic nuclei at higher and higher speeds until they crash into one another, sometimes forming heavier elements.
German physicist who discovered x-rays and developed roentgenography (1845-1923)
(Roentgen Equivalent Man) the dosage of ionizing radiation that will cause the same amount of injury to human tissue as 1 roentgen of X-rays
Radioactive dating
technique in which scientists calculate the age of a sample based on the amount of remaining radioactive isotopes it contains
radioactive tracer
a radioactive atom that is incorporated into a substance so that movement of the substance can be followed by a radiation detector
nuclear fission
A nuclear reaction in which a massive nucleus splits into smaller nuclei with the simultaneous release of energy
nuclear fusion
A nuclear reaction in which nuclei combine to form more massive nuclei with the simultaneous release of energy
critical mass
the minimum mass of a fissionable isotope that provides the number of neutrons needed to sustain a chain reaction
relatively unstable form of Uranium; nuclear fission depends on it; more rare than U-238(92 protons and 143 neutrons)
Categories: Nuclear Chemistry