Fission and Fusion of Atomic Nuclei and Radiation

Fission and Fusion of Atomic Nuclei and Radiation in Your Life

Nuclear Fission • Fission – the splitting of a nucleus into smaller fragments. (occurs by isotopes being bombarded with neutrons) – Nuclear reactions can release enormous amounts of energy! Much more than chemical reactions. Ex. 1 235 U ----> 142 Ba + 91 Kr + 31 n + energy n + 0 92 56 36 0 • Fission products from nuclear reactors are highly radioactive, remain so for a considerable period of time, and cannot simply be discarded. (Nuclear Waste) • Advantages of a fission reaction are: – Relatively little fuel is needed

Nuclear Fusion • Fusion – occurs when the nuclei combine to produce a nucleus of greater mass. (Results from fusion: energy released by the sun) Ex. 1 1 H + 11 H ---> 21 H + 0+1 e • Fusion reactions- small nuclei combine and when they do, they release much more energy than fission reactions. – Only occur at temperatures exceeding 40 million degrees Celsius!!! This high activation energy is a huge problem in utilizing this energy as an inexpensive and readily available fuel source. – One major advantage of fusion is that the products are not highly radioactive.

Risks of Radioactivity • • Biological exposure Long-term storage Disposal Nuclear Accidents

Beneficial Uses of Radioactive Isotopes • Radioactive dating – C-14 to C-12 ratio in dating living organisms – U-238 to Pb-206 ratio in dating geological formations • Detection and treatment of disease – I-131 – used for diagnosing and treating thyroid disorder – Co-60 –treats cancer – Tc-99 m – determines the location of brain tumors & detects the presence of cancerous cells in bone marrow • Industrial chemistry and measurement – Radioisotopes are used in food preservation (Radiation can kill bacteria, mold, yeast and even insect eggs. )

25. 3 Section Assessment pg. 813 #’s 17 & 20 25. 4 Section Assessment pg. 819 #’s 22 & 23 Study for Quiz Chapter 25 Study for Test Organic Chem. – Nuclear Chem.