Question

Element 'X' occurs in nature in the form of two
isotopes of atomic masses 23 u and 24 u
respectively. If its average atomic mass is 23.2 u,
then % abundance of lighter isotope is​

Answer 1

potassium

Explanation:

it occurs naturally in the nature atomic mass of 23.2

Answer 2

Answer:

The percentage abundance of the lighter isotope is 80%.

Explanation:

Let the fractional abundance of the lighter isotope be $x$.

Then the fractional abundance of the heavier isotope is $1-x$.

We know,

Average atomic mass = ∑(Atomic mass of an isotope)×(Fractional abundance)

or, 23.2 = {($x$ × 23) + 24 × $(1-x)$}

or, 23.2 = $23x + 24-24x$

or, 23.2 = $24-x$

or, $x = 24-23.2$

or, $x = 0.8$

Here, the fractional abundance of the lighter isotope is 0.8.

Hence, the percentage abundance of the lighter isotope is 80%.