Sodium isotopic

In the periodic table, sodium is listed with an atomic number of 11 and a mass number of 22.99. Create two possible sodium isotopes, giving their atomic numbers and atomic masses that are consistent with the periodic table values. 

A decrease with rising temperature has also been observed for the relative differences of the external mobilities (250°-350°C.) of the lithium isotopes in eutectic NaNOs-KNOs mixtures (2). On the other hand the relative differences of the external mobilities of the sodium isotopes Na and Na in LiNOs (305°-359°C.) and in eutectic NaNOa-KNOs mixtures (255°-374°C.) rise with rising temperature (in the latter case the increase is followed by a decrease in the range 374°-434°C.) (70). 

Sodium is monoisotopic so that investigations on isotopic separations of this element have to be carried out by means of synthetic mixtures of radioactive sodium isotopes (see Chap. 3.3, Fig. 10). The most suitable isotopes are Na and Na due to their good detectability with y-radiation. 

In Table 12 the distribution of sodium ions between water and chloroform (referred to g HjO/g CHCI3) is presented in dependence on the different polyethers. All results were obtained under analogous conditions with 0.1 mmol Na and 0.1 mmol polyether in the system where the pH-value was established to be 8 by adding 10 mmol of tetraethylammonium chloride. The establishment of the equilibrium requires less than 60 min in all systems and was followed by the y-activity of the sodium isotopes and the P-activity of C-labeled polyethers. The enrichment of one of the sodium isotopes in a practical scale from a Na/ Na-mixture can only be achieved in a system where the distribution ratio (Na ),/(Na ) g is not too high. However, in contrast to the enrichment of stable isotopes from a sample with natural isotope abundance, the enrichment of Na or of Na from an isotopic mixture is not of great importance because these two isotopes can be produced by nuclear reactions. On the other hand, the investigations on sodium isotopic separations are of common interest in respect to further knowledge about isotopic effects. 

Delphin and Horwitz investigated sodium isotopic separations in chromatographic experiments using dicyclohexano] 18]crown-6 and [18]crown-6 (see Fig. 11). A steel column was applied which was 50 cm in height and 0.3 cm in diameter and filled with the strongly acidic polystyrene resin Aminex A 7. A mixture of Na and Na which had a nearly equal decay rate for both isotopes was fixed at the top of the column and was then eluted by a solution of methanol/water (80 %/20 %,... 

Table 14. e-values of sodium isotopes in the system cation exchanger resin/solution of 1 0 M HNO3,0.025 M crown ether, 80%CH3OH (v/v) ... 

The atomic-beam laser method with non-optical detection, schematically ven in Fig. 1, was developed at Orsay and first applied to the sequence of sodium isotopes... 

A radioactive sodium isotope, such as sodium-22, with a half-life of 2.5 years, is introduced into the most active electrolyte. If there are voids in the adhesive layer, the electrolyte penetrates into the clearance between the adherends. The joint is then washed clean and examined with a radiometer. If voids are present, the radioactive substance is retained in them and the radiation intensity is higher. The application of this method in industry is limited, however, because of the danger from radiation. ... 

The body sodium is distributed into intracellular and extracellular pools. The sodium contained in these pools exchanges readily with the exogenous sodium. Isotope studies demonstrate that the intracellular sodium is rapidly exchanged with the extracellular sodium. In addition to the two large sodium pools, a smaller sodium pool is located in the skeleton. The sodium in bone is only slowly exchanged with exogenous sodium. The presence of sodium in the bone has been discussed in the chapter on calcification. 

F ure 16. Scheme for laser-rf spectroscopy of sodium isotopes with nonopticai detection. 

Write isotopic symbols of the form zX for each isotope. (a) the oxygen isotope with 8 neutrons (b) the fluorine isotope with 10 neutrons (c) the sodium isotope with 12 neutrons (d) the aluminum isotope with 14 neutrons 88. Write isotopic symbols of the form X-A (for example, C-13) for each isotope. (a) the iodine isotope with 74 neutrons (b) the phosphorus isotope with 16 neutrons (c) the uranium isotope with 234 neutrons (d) the argon isotope with 22 neutrons... 

F. Touchard, J.M. Serre, S. Buttgenbach, P. Guimbal, R. Klapisch, M. de Saint Simon, C. Thibault, H.T. Duong, P. Juncar, S. Liberman, J. Pinard, J.-L. Vialle Electric quadrupole moments and isotopic shifts of radioactive sodium isotopes. Phys. Rev C 25, 2756 (1982)... 

Vi alle "High Resolution Laser Spectroscopy of the D-Lines of On-Line Produced Radioactive Sodium Isotopes", in Laser Spectroscopy ed. by I. Haroche, J.C. Pebay-Peyroula, T.W. Hansch, S.E. Harris, Lecture Notes in Physics, Vol. 43 (Springer, Berlin, Heidelberg, New York 1975)... 

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