Created by C. Ippolito May 2007 Nuclear Chemistry 25.1 Nuclear Radiation 25.2 Nuclear Transformations 25.3 Fission and Fusion of Atomic Nuclei 25.4 Radiation in Your Life Updated 4/26/2019 Created by C. Ippolito May 2007

Created by C. Ippolito May 2007 Nuclear Radiation Objectives Explain how an unstable nucleus releases energy Describe the three main types of nuclear radiation Updated 4/26/2019 Created by C. Ippolito May 2007

Created by C. Ippolito May 2007 Radioactivity Antoine Becquerel, Marie and Pierre Curie studied rays from uranium “exposed” film Radioactivity the process of “releasing” rays Radiation penetrating rays and particles released Radioisotopes unstable nuclei release energy during radioactive decay Updated 4/26/2019 Created by C. Ippolito May 2007

Created by C. Ippolito May 2007 Types of Radiation Alpha Radiation (α) two protons and two neutrons ( ) Beta Radiation (β) electron ( ) or positron ( ) Gamma Radiation (γ) high energy photon Updated 4/26/2019 Created by C. Ippolito May 2007

Created by C. Ippolito May 2007 Updated 4/26/2019 Created by C. Ippolito May 2007

Created by C. Ippolito May 2007 Updated 4/26/2019 Created by C. Ippolito May 2007

Created by C. Ippolito May 2007 5/18 section 3 Updated 4/26/2019 Created by C. Ippolito May 2007

Nuclear Transformations Objectives Describe the type of decay a radioisotope undergoes Solve problems that involve half-life Identify the two ways transmutation can occur Updated 4/26/2019 Created by C. Ippolito May 2007

Nuclear Stability and Decay Nuclear Force holds all nuclear particles together stronger than electromagnetic forces Band of Stability neutron to proton ratio for stable nuclei Updated 4/26/2019 Created by C. Ippolito May 2007

Created by C. Ippolito May 2007 Half-Life Half-life (t½) time required for one-half of the nuclei of a radioisotope to decay to products after each half-life, half of the existing radioactive atoms have decayed into atoms of a new element Table N – Radioisotopes half-life decay type Updated 4/26/2019 Created by C. Ippolito May 2007

Half-life Calculations Updated 4/26/2019 Created by C. Ippolito May 2007

Created by C. Ippolito May 2007 Transmutation an atom of one element turns into an atom of another element TWO WAYS: radioactive decay particle bombardment transuranium elements all elements above 92 synthesized by bombardment in reactors and particle accelerators Updated 4/26/2019 Created by C. Ippolito May 2007

Fission and Fusion of Atomic Nuclei Objectives Describe what happens in a nuclear chain reaction Explain the role of water in the storage of spent fuel rods Distinguish fission reactions from fusion reactions Updated 4/26/2019 Created by C. Ippolito May 2007

Created by C. Ippolito May 2007 Nuclear Fission Fission neutron bombardment of isotopes splits nuclei into fragments energy released used to produce steam in power plants to run dynamos Chain Reaction neutron produced react with other atoms producing more neutrons Neutron Moderation slow down neutrons so reactor fuels can capture them to maintain chain reaction Neutron Absorption decreases number of slow neutrons to slow down or stop reaction “control rods” usually made of cadmium Updated 4/26/2019 Created by C. Ippolito May 2007

Created by C. Ippolito May 2007 Nuclear Fusion Fusion nuclei combine to produce a nucleus of greater mass occurs in the sun Updated 4/26/2019 Created by C. Ippolito May 2007

Created by C. Ippolito May 2007 Radiation in Your Life Objectives Identify three devices that are used to detect radiation Describe how radioisotopes are used in medicine Updated 4/26/2019 Created by C. Ippolito May 2007

Created by C. Ippolito May 2007 Detecting Radiation Geiger Counter gas filled tube detects radiation (α,β,γ) Scintillation Counter phosphor coated surface detects radiation (α,β,γ) Film Badge several layers of photographic film used to determine exposure of workers Updated 4/26/2019 Created by C. Ippolito May 2007

Created by C. Ippolito May 2007 Radiation Usage Medical Diagnosis radioisotope tracers follow metabolic paths Medical Treatment destroy cancerous cells Radioactive Dating determine age of fossils Updated 4/26/2019 Created by C. Ippolito May 2007