Chapter 28 Nuclear Chemistry
Nuclear Radiation Nuclear Transformations Fission and Fusion Radiation in Your Life
Ch 28.1 Nuclear Radiation
Radioactivity Types of Radiation
Radioactivity
Radioisotopes – an isotope that has an unstable atomic nucleus and undergoes radioactive decay
Always accompanied by large emissions of energy
Not affected by temp., pressure, or catalysts Can not speed up or slow down the reaction or
turn off
Radioactivity
Marie Curie – (1867-1934) named the process
Process by which unstable atomic nuclei achieve stability
Won Nobel Peace Prize – 1903 along with Pierre Curie and Antoine Henri Becquerel
Radiation
Penetrating rays and particles emitted by a radioactive source
Types of Radiation
Alpha Beta Gamma
Alpha
Helium nuclei emitted from a radioactive source
Alpha particles Contain 2 protons and 2 neutrons and
have a double positive charge 4
2He or Can be stopped by a sheet of paper or
your skin
Beta
Fast moving electrons formed by the decomposition of a neutron
Beta Particles 0
-1e or Can be stopped by aluminum foil or pieces
of wood
Gamma
High energy electromagnetic radiation No mass, no charge Can almost be stopped by several feet of
concrete or several inches of lead
Chernobyl
April 26, 1986 at 1:23:44am Reactor 4 exploded Released 30-40 times the amount of
radiation as bombing Japan did
Chapter 28.2 Nuclear Transformations
Nuclear Stability and Decay Half – Life Transmutation Reactions
Nuclear Stability and Decay
1500 different nuclei, only 264 are stable For low atomic number (up to 20), the ratio
of protons to neutrons is 1(ratio of stability) 12
6C 147N
Atomic numbers above 20, have a ratio of protons to neutrons of 1.5(ratio of stability) 206
82Pb
Beta Emissions
6629Cu 66
30Zn + 0-1e
146C 14
7N + 0-1e
Positron
Particle with the mass of an electron, but a positive charge
0+1e
85B 8
4Be + 0+1e
Alpha Emission
All nuclei with an atomic number greater than 83 are radioactive
20482Pb 200
80Hg + 42He
22688Ra 222
86Rn + 42He
Half Life
The time required for one half of the nuclei of a radioisotope sample to decay to products
Artificial Radioisotopes
Usually have very short half lives Used in nuclear medicine
PET Scan - Positron Emission Tomography
Brain Function
Thyroid TumorsDog
Iodine 131
Bone Fractures
Technetium
Radioactive Isotope UseC-14 Used to determine the age of biological remains (archaeology)I-131 Used to detect and cure hyperthyroidism (overactive thyroid)Co-60 Used as a source of radiation for radiotherapy of cancerTc-99m Used to image blood vessels, especially in the brain, to detect tumorsPu-239 Used as a highly fissionable fuel source for nuclear power or nuclear weaponsAm-241 Used in tiny amounts in smoke detectors as a source of ions to make a currentU-235 Used as fissionable fuel source for nuclear power or nuclear weaponsU-238 Used to determine the age of uranium-containing rock formations (geology)
