Nuclear chemistry atomic bomb

Any powerful technology has two faces. In fact, the adverse connotations of nuclear power (e.g. atomic bombs, radioactive pollution) are offset by important positive applications (e.g. in nuclear medicine). Sensors have two opposing faces as well. On the one hand, they make a major choice for the Analytical Chemistry of the XXI century on the other, the ease with which they can output signals (and hence results) may induce careless (non-contrasted) use and obtainment of spurious analytical information, particularly in the hand of non-experts (e.g. physicians, engineers) obviously lacking... 

One of the best accounts of the early development of atomic and nuclear chemistry is R. Rhodes, The Making of the Atom Bomb (New York Simon Schuster, 1986). 

J Ju elements in the periodic table exist in unstable versions called radioisotopes (see Chapter 3 for details). These radioisotopes decay into other (usually more stable) elements in a process called radioactive decay. Because the stability of these radioisotopes depends on the composition of their nuclei, radioactivity is considered a form of nuclear chemistry. Unsurprisingly, nuclear chemistry deals with nuclei and nuclear processes. Nuclear fusion, which fuels the sun, and nuclear fission, which fuels a nuclear bomb, are examples of nuclear chemistry because they deal with the joining or splitting of atomic nuclei. In this chapter, you find out about nuclear decay, rates of decay called half-lives, and the processes of fusion and fission. 

Fermi, Enrico. (1901-1954). An Italian physicist who later became a U.S. citizen. He developed a statistical approach to fundamental problems of physical chemistry based on Pauli s exclusion principle. He discovered induced or artificial radioactivity resulting from neutron impingement, as well as slow or thermal neutrons. He was professor of physics at Columbia (1939) and awarded the Nobel Prize in physics in 1938. He was the first to achieve a controlled nuclear chain reaction, directed the construction of the first nuclear reactor at the University of Chicago (1942), and worked on the atomic bomb at Los Alamos. He also carried on fundamental research on subatomic particles using sophisticated statistical techniques. Element 100 (fermium) is named after him. 

Nuclear chemistry is very much in the news today. In addition TO APPLICATIONS IN THE MANUFACTURE OF ATOMIC BOMBS, HYDROGEN BOMBS, AND NEUTRON BOMBS, EVEN THE PE.A.CEFUL USE OF NUCLEAR ENERGY HAS BECOME CONTROVERSIAL, IN PART BECAUSE OF SAFETY CONCERNS ABOUT NUCLEAR POWER PLANTS AND ALSO BECAUSE OF PROBLEMS WITH DISPOSAL OF RADIOACTIVE WASTES. IN THIS CHAPTER WE WILL STUDY NUCLEAR REACTIONS, THE STABILITY OF THE ATOMIC NUCLEUS, RADIOACTIVITY, AND THE EFFECTS OF RADIATION ON BIOLOGICAL SYSTEMS. 

With the discovery of the neutron as a fundamental particle, many paradoxes of physics and chemistry were finally resolved, and new areas of research evolved. Prior to the discovery of the neutron as a fundamental particle, scientists generally believed that the nucleus was comprised of protons and nuclear electrons. However, one could not explain, for example, the spin of nuclei with that model. Now, at last, theory could predict the properties of the nucleus quite well. Also, since neutrons are not repelled by the charge on the atomic nucleus, they interact easily with nnclei. Nen-tron scattering enables the determination of crystal stmctnres by probing the positions of nuclei in a sample. Neutrons can also catalyze fission reactions, for example, the fission of uranium nuclei that led to the creation of nuclear power plants and the atomic bomb. 

Ihe approximation of separating electronic and nuclear motions is called the Bomr-Oppenheimer approximation and is basic to quantum chemistry. [The American physicist J. Robert Oppenheimer (1904-1967) was a graduate student of Bom in 1927. During World War II, Oppenheimer directed the Los Alamos laboratory that developed the atomic bomb.] Born and Oppenheimer s mathematical treatment indicated that the tme molecular wave function is adequately approximated as... 

This branch of chemistry began with the discovery of natural radioactivity by Antoine Becquerel and grew as a result of subsequent investigations by Pierre and Marie Curie and many others. Nuclear chemistry is very much in the news today. In addition to applications in the manufacture of atomic bombs, hydrogen bombs, and neutron bombs, even the peaceful use of nuclear energy has become controversial, in part because of safety concerns about nuclear power plants and also because of problems with radioactive waste disposal. In this chapter, we wiU study nuclear reactions, the stability of the atomic nucleus, radioactivity, and the effects of radiation on biological systems. 

The chapters of Part I give you a background in chemistry basics. I tell you about matter and the states it can exist in. I talk a little about energy, including the different types and how it s measured. I discuss the microscopic world of the atom and its basic parts. I explain the periodic table, the most useful tool for a chemist. And I cover radioactivity, nuclear reactors, and bombs. 

The discovery of nuclear chemistry has had profound impacts on society. Since the testing of the first atomic bomb in 1945, humans have lived under the threat of possible nuclear annihilation. During the Cold War years, the United States and the Soviet Union built over 100,000 nuclear weapons, enough to destroy every major city in the world. Today, many of these weapons have been disarmed, and nuclear arsenals are much smaller. 

The study of radiation is part of nuclear chemistry. In contrast to ordinary chemistry, which involves changes with the electrons of atoms and molecules, nuclear chemistry involves changes within the nuclei of atoms. When these changes occur, the nuclei emit energetic particles that we call radiation. We will see how the chance discovery of radiation eventually led to the development of the atomic and hydrogen bombs. We will also study several peacetime applications of radiation such as nuclear power and nuclear medicine. 

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