Radium series

The Uranium-Radium Series. This series commences with 318U and ends with the stable isotope n6Pb. The decay scheme is represented by ... 

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... 

Rn is formed by the alpha disintegration of 226Ra. Actinon, its isotope of mass number 219, is produced by alpha disintegration of 223 Ra (AcX) and is a member of the Actinium Series. Similarly, thoron, its isotope of mass number 220. is a member of the thorium senes. Since the name radon may be considered to be specific for the isotope of mass number 222 (from the radium series), the term emanation is sometimes used for element number 86 in general. Other isotopes of radon include those of mass numbers 209-218 and 221. 

The great variety of radionuclides present in thorium and uranium ores are listed in Tables 4.1, 4.2 and 4.3. Whereas thorium has only one isotope with a very long half-life (- Th), uranium has two and giving ri.se to one decay scries for Th and two for U. In order to distinguish the two decay series of U, they were named after long-lived members of practical importance the uranium-radium series and the actinium series. The uranium-radium series includes the most important radium isotope ( Ra) and the actinium scries the most important actinium isotope ( Ac),... 

The nuclear reactions in the uranium-radium series are shown in Figure 3S-2. The principal isotope of uranium, constitutes... 

The 4n series - the thorium series The 4n + 1 series — the neptunium series The 4n + 2 series = the uranium-radium series The 4n + 3 series - the uranium-actinium series... 

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. 

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. ... 

The main source of terrestrial radiation is long-living isotopes of the uranium-radium series the thorium series ( Th) and the actinium series... 

This analysis can, for example, be applied to multistep radioactive decay reactions and to isomerization reactions. In such multistep processes, every step is by definition a first-order process. An example of multistep radioactive decay is the Actinium series (see Lederer et ah, 1968), in which Bi alpha-decays to ° T1, which beta-decays to ° Pb with respective half-lives of 2.14 and 4.77 min. Therefore, in this two-step consecutive process, k J ki =/9 = 2.14/4.77 = 0.449, very close to the Acme point. Similarly, in the Radium series, Pb beta-decays to which beta-decays to Po, which then alpha-decays very rapidly (with a half-life of only 0.16 ms) to ° Pb. This multistep decay can be closely approximated by two steps, the first with a half-life of 27 min, the second with a half-life... 

Fig. 12.9 The separation of products B and C and attainment of equilibrium in the radium series as a function of potential established by different metal-metal ion systems [15]...

L. BriUouin, Le Journal de Physique et le Radium Series VII, Tome III, 373, 1932. 

Uranium-radium series (half-life time of 4.4 x 10 years)... 

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