Isotopic radioactive

Baeza A, del Rio M, Miro C, et al. 1999. Recent evolution of the multi-isotopic radioactive content in ice of Livingston Island, Antarctica. Bull Environ Contain Toxicol 63 139-149. 

In these equations, In is the natural logarithm, Nt is the amount of isotope radioactive at some time t, N0 was the amount of isotope radioactive initially, and k is the rate constant for the decay. If you know initial and final amounts and if you are looking for the half-life, you would use equation (1) to solve for the rate constant and then use equation (2) to solve for t1/2. 

The Development of Modern Chemistry. Harper and Row, New York, 1964, xii + 851 pp. including illustrations, Appendixes, (Discovery of the Elements, Discovery of Natural Radioactive Isotopes, Radioactive Decay Series, Nobel Prize Winners in Chemistry, Physics, and Medicine), and Bibliographic Notes. 

Symbol Pu atomic number 94 atomic weight 244 an actinide series transuranium element a man-made radioactive element electron configuration [Rn]5/ 7s2 partially filled f suhsheU valence states +3, +4, -i-5, +6 eighteen isotopes in the mass range 228-230, 232-246 aU isotopes radioactive the longest lived isotope Pu-244, ti/2 8.2x10 year the shortest hved isotope Pu-233, ti/2 20.9 minute. 

In this chapter, we introduced the constituents and structure of the atom and showed that elements typically have several isotopes (same number of protons but different numbers of neutrons). Using the Chart of the Nuclides, we briefly discussed the distribution and stability of the isotopes. Radioactive isotopes were introduced, and we mentioned that they can be used for dating of geological and cosmochemical events. We then discussed the periodic... 

BERKELIUM. [CAS 7440-40-6]. Chemical element, symbol Bk, at. no. 97, at wt. 247 (mass number of the most stable isotope), radioactive metal of the Actinide series, also one of the Transuranium elements. All isotopes of berkelium are radioactive all must be produced synthetically. The element was discovered by G.T. Seaborg and associates at the Metallurgical Laboratory of the University of Chicago in 1949. At that time, the dement was produced by bombarding 241 Am with helium ions. 4i Bk is an alpha-emitter and may be obtained by alpha-bombardment of ,4Cm. 245Cm. or 246Ciu. Ollier nuclides include those of mass numbers 243—246 and 248-250. Probable electronic configuration ... 

EINSTENIUM. CAS 7429-92-71. Chemical element symbol Es, at. no. 99. at. wt. 254 (mass number of the most stable isotope), radioactive metal of the Actinide series, also one of the Transuranium elements. Both einsteinium and fermium were formed tit a thermonuclear explosion that occurred in the South Pacific in 1952. The elements were identified by scientists from the University of California s Radiation Laboratory- the Argonnc National Laboratory, and the I. os Alamos Scientific Laboratory. It was observed that very heavy uranium isotopes which resulted from the action of the instantaneous neutron dux on uranium (contained in the explosive device) decayed to form Es and Fm. The probable electronic configuration of Es is... 

NEPTUNIUM. [CAS 7439-99-8]. Chemical element, symbol Np, at. no, 93, at. wt, 237,0482 (predominant isotope), radioactive metal of the Actinide series, also one of the Transuranium elements. Neptunium was the first of [he Transuranium elements [o be discovered and was first produced by McMillan and Abelson (1940) at the University of California at Berkeley. This was accomplished by bombarding uranium with neutrons. Neptunium is produced as a by-pruduct from nuclear reactors. 237Np is the most stable isotope, with a half-life of 2.20 x 106 years, The only other very long-lived isotope is that of mass number 236. with a half-life of 5 x 10- years. 

An isotopic radioactive tracer commonly is used for radionuclides that have no stable isotopes, notably for high-Z radionuclides that emit alpha particles. They also may be applied if a carrier is available as a more convenient way of determining the yield. A non-isotopic radionuclide can function as tracer for procedural steps in which it and the analyte react identically. 

Radioactive Isotopes Radioactive Emanations Separating Nuclear Emanations Nuclear Fusion and Fission Half-Life (t1/2)... 

These questions can be answered by using diffusion markers. Atoms of one element (or both) can be marked by a radioactive or stable isotope. Radioactive Si (half... 

The stable isotopes have nuclei that do not decay to other isotopes on geologic timescales, but may themselves be produced by the decay of radioactive isotopes. Radioactive (unstable) isotopes have nuclei that spontaneously decay over time to form other isotopes. For example, C, a radioisotope of carbon, is produced in the atmosphere by the interaction of cosmic-ray neutrons with stable... 

Radioactive Isotopes - Radioactive isotopes of metals are widely used in medical therapy and diagnosis. A tabulated review references this area in detail. ... 

Iodine, elemental Iodine, resublimed Iron sulfate Isotopes, radioactive Laboratory chemicals, inorganic... 

Potassium is also famous for one of its isotopes, radioactive potassium-40, which has a long half-life of 1.25 billion years. (Half-life refers to the amount of time it takes for half of the elements atoms to disintegrate.) Potassium-40 occurs naturally and is used by researchers to determine the age of rocks. As potassium-40 decays, it becomes a noble gas called argon. By determining how much argon is present in a rock, researchers can estimate the rock s age. Using this technique, scientists have estimated some rocks on Earth to be as old as 3.8 billion years. 

Certain isotopes (radioactive isotopes) of elements emit particles and energy that can be used to trace the behavior of biochemical systems. These isotopes otherwise behave identically to any other isotope of the same element. Their chemical behavior is identical it is their nuclear behavior that is unique. As a result, a radioactive isotope can be substituted for the "nonradioactive" isotope, and its biochemical activity can be followed by monitoring the particles or energy emitted by the isotope as it passes through the body. 

Why are some isotopes radioactive but others are not Do all radioactive isotopes decay at the same rate Are all radioactive materials equally hazardous We address these and other questions in this section. 

Competition methods are employed for ratios of less than 5-10% when two isotopic species react at different rate a mixture of the two will change composition (except at 100% reaction) and yield a product having a different isotopic composition from the reactant. This will give us a measure of the isotope effect. Radioactive isotopes give specific radiation (counts/sec/mole) proportional to the ratio of radioactive over stable isotope radioactivity may be measured with a precision better than 1%. 

Environmental Potential sources Isotope Radioactive significance in soil... 

No stable isotopic carrier is available (e.g., for promethium, technetium, radium and its progeny, and the actinides and transactinides). Either nonisotopic carrier or isotopic radioactive tracer can be substituted (see next section). The special problems that arise are discussed in Section 7.2.2. 

In the second case were utilized cosmogenic radioactive isotopes, which form in the upper atmosphere the effect of cosmic irradiation. This method is based on the assumption that the content of these nuclides in the atmosphere is stable as a consequence of equilibrium between rates of their formation and decay. These get into the subsurface with atmospheric precipitation, and their content consistently declines with time according to equation (2.358). The age in this case is determined as a function of the ratio of cosmogenic isotopes radioactivity value in the atmosphere and in the sample instead of and in equation (2.358) ... 

---