Radioactive series, actinium uranium

The isotope 38U is the parent of the natural uranium 4n + 2 radioactive senes, and the isotope -3 >U is the parent of the natural actinium 4n + 3 radioactive series. 

Daughters of alpha emitters The recoil method can also be useful for the separation of daughter products produced by a decay of a parent. This technique has been applied to studies of short-lived daughters In the radioactive decay series of uranium, thorium, and actinium (175) ... 

The series of Radioactive disintegrations the uranium-radium series, the uranium-actinium series, the thorium series, and the neptunium series. The age of the earth. The fundamental particles electron, proton, positron, neutron, positive, negative, and neutral mesons, neutrino. The photon (light quantum) the energy of a photon, hv. Planck s constant. The wave-particle duality of light and of matter. The wavelengths of electrons. 

The exponential laws of radioactive-series decay and growth of radionuclides were first formulated by Rutherford and Soddy in 1902, to explain their results (Rutherford and Soddy 1902,1903) on the thorium series of radionuclides. In 1910, Bateman (Bateman 1910) derived generalized mathematical expressions that were used to describe the decay and growth of the naturally occurring actinium, uranium, and thorium series until the discovery of nuclear fission and other new radioactive decay series were found in the 1940s. For the description of half-lives and decay constants, activities and number of radionuclides involved in the decay of two radionuclides, Friedlander et al. (1981) have given a representative overview (see also O Chap. 5 in Vol. 1). 

The chain of radioactive decay that begins with continues through a number of steps of a and j8 emission until it eventually terminates with a stable isotope of lead— 82 1. The entire scheme is outlin in Figure 25-2. All naturally occurring radioactive nuclides of high atomic number belong to one of three radioactive decay series the uranium series just described, the thorium series, or the actinium series. (The actinium series actually begins with uranium-235, which was once called actino-uranium.)... 

Various radium isotopes are derived through a series of radioactive decay processes. For example, Ra-223 is derived from the decay of actinium. Ra-228 and Ra-224 are the result of the series of thorium decays, and Ra-226 is a result of the decay of the uranium series. 

ISOTOPES There are 41 isotopes of polonium. They range from Po-188 to Po-219. All of them are radioactive with half-lives ranging from a few milliseconds to 102 years, the latter for its most stable isotope Po-209. Polonium is involved with several radioactive decay series, including the actinium series, Po-211 and Po-215 the thorium series, Po-212 and Po-216 and the uranium decay series, Po-210, Po-214, and Po-218. 

F. Soddy, A. S. Russell, and K. Fajans independently predicted the existence of a new member of the uranium series of radioactive elements and that it would occupy the vacant place just below tantalum in the Va group of the periodic system. Protactinium, the patriarch of the actinium series of elements, was discovered in 1917 independently by Otto Hahn and Miss Lise Meitner, by K. Fajans, and by Frederick Soddy, John A. Cranston, and A. Fleck (47, 49, SO). 

One of the most important observations of atoms is the set of relationships between elements that belong to one of the series of radioactive decays. The parent elements of uranium, thorium and actinium decay through many intermediates to the stable element lead. The Nobel Prize in Chemistry for 1921 was awarded in 1922 to Frederick Soddy for his complete characterization of these processes. The story is beautifully told in his Nobel Lecture entitled The origins of the conception of isotopes (25). 

I he atomic wcighi varies because of natural variations in the isotopic composition of the element, caused by the various isotopes having different origins - I h is the end product of the thorium decay scries, while Ph and " Pb arise Irom uranium as end products of the actinium and radium series respectively. Lead-204 has no existing natural radioactive precursors. Electronic configuration l.v 2s lfc22/j"3v 3//,3i/l"4v- 4/, 4l/" 4/ IJ5v- 5/ "5t/l"bv />-. Ionic radius Pb I.IX A. Pb 1 0.7(1 A. Metallic radius 1.7502 A. Covalent radius (ip i 1.44 A. First ionization potential 7.415 cV second. 14.17 eV. Oxidation... 

It has been observed that the element lead occurs in unaltered primary uranium minerals in amounts proportional to the amount of uranium present. It is not radioactive, but its atomic -weight differs from that of ordinary lead, being very little more than 206. It is regarded as highly probable that this element is the end-product of the radium series, so that like radium and actinium it is derived from uranium. It is an isotope of lead, with which it is therefore chemically identical, and is kno-wn as Radium G. It is often referred to as uranium lead. ... 

Many of the radioactive isotopes that occur in nature are related to each other. For example, when uranium-235 breaks apart, it forms a new isotope, thorium-231. But thorium-231 is radioactive also. It breaks apart to form protactinium-231. And protactinium-231 is also radioactive. It breaks apart to form actinium-227. This series goes on for 14 more steps until a stable isotope is finally formed. 

CAS 7439-92-1. Pb. Metallic element of atomic number 82, group IVA of the periodic table, aw 207.2, valences = 2,4, four stable isotopes. The isotopes are the end products of the disintegration of three series of natural radioactive elements uranium (206), thorium (208), and actinium (207). 

Actinium is a member of a third radioactive seres, known as the actinium series, which originates in actino-uranium, an isotope of uranium I with a half-life period of 4 X io8 years. It occurs in all uranium minerals in a constant ratio to UI whatever the age. 

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