Isotopes, of carbon, use

Exponentials play a useful role in understanding nuclear disintegrations and half-lives. For example, 14C, a radioactive isotope of carbon used for carbon dating, has a half-life / /2 = 5730 years before it converts into stable 147V. This means that the number... 

C. (carbon-14). The naturally occurring radioactive isotope of carbon used in chemical dating, tracer studies, etc. 

Most CO and CO2 in the atmosphere contain the mass 12 isotope of carbon. However, due to the reaction of cosmic ray neutrons with nitrogen in the upper atmosphere, C is produced. Nuclear bomb explosions also produce C. The C is oxidized, first to CO and then to C02 by OH- radicals. As a result, all CO2 in the atmosphere contains some 0, currently a fraction of ca. 10 of all CO2. Since C is radioactive (j -emitter, 0.156 MeV, half-life of 5770 years), all atmospheric CO2 is slightly radioactive. Again, since atmospheric CO2 is the carbon source for photos5mthesis, aU biomass contains C and its level of radioactivity can be used to date the age of the biological material. 

Recently it has been recognised that the carbon isotope composition of small amounts of plant material may be used to assess differences inpi/pa and W (Farquhar et al., 1982). There are two stable isotopes of carbon, and C, which are in the molar ratio 1 89 in the atmosphere. During assimilation of atmospheric CO2 the plant fixes a smaller ratio... 

Radioactive decay is a nuclear process from an intrinsically unstable nucleus that emits alpha particles, beta particles and gamma rays. The loss of mass from the nucleus changes the element to one of a lower mass. Carbon dating uses the decay of the 14C nucleus, a heavy and unstable isotope of carbon, to become the stable 14N isotope. The overall process is written ... 

At one time, the hydrogen atom with one proton and no neutron was used as the standard to define 1 atomic mass unit (1 amu). Today, chemists use carbon-12, the most abundant isotope of carbon for the standard amu, which is defined as 1/12 of the C-12 atom. Therefore, the actual atomic weight for an element is in average mass units (numbers), taking into account all the isotopes (atoms) of that element. 

Examples of isotopes are abundant. The major form of hydrogen is represented as H (or H-1), with one proton H, known as the isotope deuterium or heavy hydrogen, consists of one proton and one neutron (thus an amu of 2) and is the isotope of hydrogen called tritium with an amu of 3. Carbon-12 ( C or C-12) is the most abundant form of carbon, though carbon has several isotopes. One is the C isotope, a radioactive isotope of carbon that is used as a tracer and to determine dates of organic artifacts. Uranium-238 is the radioactive isotope (Note The atomic number is placed as a subscript prefix to the element s symbol—for example, —and the atomic mass number can be written either as a dash and number fol-... 

Two dominant themes run throughout the evolution of late type star compositions the abundances of the isotopes of carbon, nitrogen, and oxygen, and the abundances of the metals heavier than the iron peak - the neutron capture elements usually associated with the s-process. In addition to these elements, the abundance of lithium can also be a distinguishing characteristic of some groups, and can be used to interpret possible origins for some of these peculiar stars. 

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