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Determination of atomic and isotopic mass - class-XI
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There are two isotopes of an element with atomic mass $z$. Heavier one has atomic mass $z+2$ and lighter one has $z-1$, then an abundance of lighter one is:
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A
$66.6\%$
💡 Explanation:
Abundance of an isotope can be calculated as :
Let abundance of isotope with atomic mass $Z+2$ is x
Then abundance of isotope $Z-1$ is $1-x$
$(Z+2)x+(Z-1)(1-x)\quad =Z$
On solving this, we get
$x=\dfrac { 1 }{ 3 } $
Therefore,% abundance of isotope with atomic no.$Z+2$ is =$=\dfrac { 1 }{ 3 } \times 100=33.33$%
Therefore,% abundance isotope with atomic no. $Z-1$ is =$100-33.33=67.66%$%
Therefore isotope with atomic $Z-1$ is higher in % abundance