Radioactivity and Nuclear Bombardment Reactions

In chemical reactions, only the outer electrons of the atoms are disturbed. The nuclei of the atoms are not affected. In nuclear reactions, however, the nuclear changes that occur are independent of the chemical environment of the atom. For example, the nuclear changes in a radioactive iH atom are the same if the atom is part of an H2 molecule or incorporated into H2O. 

We will look at two types of nuclear reactions. One type is radioactive decay, the process in which a nucleus spontaneously disintegrates, giving off radiation. The radiation consists of one or more of the following, depending on the nucleus electrons, nuclear particles (such as neutrons), smaller nuclei (usually helium-4 nuclei), and electromagnetic radiation. 

The second type of nuclear reaction is a nuclear bombardment reaction, a nuclear reaction in which a nucleus is bombarded, or struck, by another nucleus or by a nuclear particle. If there is sufficient energy in this collision, the nuclear particles of the reactants rearrange to give a product nucleus or nuclei. First, we will look at radioactive decay. 

The phenomenon of radioactivity was discovered by Antoine Henri Becquerel in 1896. He discovCTed that photographic plates develop bright spots when exposed to uranium minraals, and he concluded that the minerals give off some sort of radiation. 

Image of a person s skeleton obtained using an excited form of technetium-99 

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