of isotopes are nuclides with same ordinal number, but different mass number. Isotopes stand at the same place (griech. ισο [ISO] - same, τόπος [topos] - place) in the periodic system (have thus the same ordinal number), but at different place in that Nuclide map. An isotope covers thus atoms of an element, which differ only by the different number of neutrons in the atomic nucleus.

The term isotope decreases/goes back on Frederick Soddy , which received 1921 among other things for it the Nobelpreis for chemistry.

Usually each naturally occurring element possesses in or few sturdy isotopes, while the other isotopes are radioactive (is called unstable) and sooner or later disintegrated. There are however also elements, with which all isotopes are unstable and disintegrated.

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sturdy isotopes

with 10 sturdy isotopes has tin most naturally occurring isotopes. Ofonly a sturdy isotope exists to 20 so-called pure elements. Such elements are called also anisotop. These are: Beryllium, Fluor, Natrium, Aluminium, Phosphor, Scandium, Mangan, Kobalt, Arsen, Yttrium, Niob, Rhodium, Iodine, cesium, praseodymium, terbium, holmium, thulium, gold, bismuth.

Thorium possesses only a natural isotope, this is however not stable. The radioactive half-life is with 1,4 · 10 10 years very long.In some text books it becomes as 21. Pure element specified. According to newer investigations so far for isotope stably held of the bismuth an alpha emitter with extremely long radioactive half-life (1,9 is · 10 19 years). Therefore strictly taken only 19 pure elements exist alsosturdy isotope.

most well-known isotopes

a well-known isotope is radioactive 14 C, which are used for the age determination by organic materials (archaeology) (radio carbon method). Carbon (C) is present mainly as sturdy isotope 12 C.

For the investigation of Paläo temperatures above all (stable) 18 O one consults.

The isotope 235 U is enriched from the nature uranium and used as fuel in nuclear power stations or more strongly enriched in atom bombs.

chemical reactions with isotopes

In their chemical reactions isotopes differ slightly. An example is the electrolysis of water, with which preferably water reacts with the normal 1 H and is divided into hydrogen and oxygen, during itself water molecules with 2 H (Deuterium, heavy hydrogen) in the residual water enrich. Reason for this are the different zero-point energies of the isotopes.

This difference in reactivity is particularly pronounced with hydrogen/deuterium due to the large relative mass difference; with most other elements these effects are around inMultiple more weakly.

isotopes with respect to analytics

(see also isotope investigation)

also at their spectral lines to be able when high resolution different isotopes of an element to be differentiated (Isotopieverschiebung).

The isotope composition in a sample usually becomes with one Mass spectrometer determines.

Radioactive isotopes can be detected also on the basis their radioactivity.

Furthermore isotopes play a role in the NMR spectroscopy. Thus for example 13 C the isotope spectroscopy ore becomes, there it contrary to 12 C in the NMR spectroscopy of organic compoundsa detectable nuclear spin has.

Isotopes become also in the clearing-up of reaction mechanisms or Metabolismen with the help of the so-called. Isotope marking uses.

The isotope composition of the water is different and characteristic at different places of the world. These differences permit it for instance with food like wine or cheese to examine the declaration of the place of origin.

designated isotopes

gives only few isotopes, for which own names or own contractions are common:

  • 2 the H-isotope deuterium (D) is usually called
  • that 3 H-isotope usually tritium (T) called

see also


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