Natural abundance

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Natural abundance is the prevalence of different isotopes of an element as found in Earth naturally. The relative atomic mass (a weighted average) of these isotopes is the atomic weight listed for the element in the periodic table. The abundance of an isotope varies from planet to planet but remains relatively constant in time.

As an example, uranium has 3 naturally accuring isotopes: U-238, U-235 and U-234. Their respective NA (natural abundance) is 99.2745%, 0.72% and 0.0055%, meaning that if, say, 100 000 uranium atoms were analysed, one whould expect to find aproximately 99 274 U-238 atoms, 720 U-235 atoms and finally no more than 5 or 6 U-234 atoms. This is not surprising as U-238 is much more stable than U-235 or U-234 (evident wile looking at the isotopes half-life: 4.468×109 years for 238U compared to 7.038×108 y for 235U and 245 500 y for 234U).

[edit] See also

af:Natuurlike verspreiding

ar:توافر طبيعي للنظائر الكيميائية ast:Abondanza natural ca:Abundància natural es:Abundancia natural hu:Természetes előfordulás ja:天然存在比 pt:Abundância natural sl:Pogostost izotopa zh:丰度

Natural abundance

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