Chemical Connections radioactive decay

In Chapter 12, the concept of half-life was used in connection with the time it took for reactants to change into products during a chemical reaction. Radioactive decay follows first order kinetics (Chapter 12). First order kinetics means that the decay rate... 

Radioactive decay processes involve the emission of a particle and/or photon (a gamma ray) from the nucleus of an atom. (See Chemical Connection 5.3.8.1 Radioactive Decay—A First-Order Reaction). Alpha decay is the ejection of an alpha particle from the nucleus of the atom (Equation 5.3.8.1) and produces a daughter nucleus that has two fewer protons and a decrease of four mass units. The velocity of the alpha particle accounts for the energy range of 4-6 MeV shown in Table 5.3.8.1. While alpha radiation can cause damage to tissues, it can only do so if the source is ingested or inhaled because the energy of alpha emitters is usually very weak and can readily be stopped by a sheet of paper. 

Abstract At present there are over 3,000 known nuclides (see the Appendix in Vol. 2 on the Table of the Nuclides ), 265 of which are stable, while the rest, i.e., more than 90% of them, are radioactive. The chemical applications of the specific isotopes of chemical elements are mostly connected with the latter group, including quite a number of metastable nuclear isomers, making the kinetics of radioactive decay an important chapter of nuclear chemistry. After giving a phenomenological and then a statistical interpretation of the exponential law, the various combinations of individual decay processes as well as the cases of equilibrium and nonequilibrium will be discussed. Half-life systematics of the different decay modes detailed in Chaps. 2 and 4 of this volume are also summarized. 

As researchers performed experiments that advanced them along the row of actinide elements on the Periodic Table, the general trends with increasing atomic number were smaller production probabilities expressed as cross sections (a consequence of the diminishing fission barrier and higher fission probabilities), an increased probability of decay by a-particle emission (a consequence of increasing a-decay Q values) and shorter half-lives. For the elements below fermium, spontaneous fission is not an important decay mode. Experimental work was dominated by radiochemical techniques in which atomic number was determined by chemical properties and atomic mass was determined by mass spectrometry and the connections of nuclei to one another by the processes of radioactive decay. The physical separation and detection methods that were used in later work were developed in the 1960s. 

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