<u>Answer:</u> The percentage abundance of and isotopes are 37.10% and 62.90% respectively.
<u>Explanation:</u>
Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.
Formula used to calculate average atomic mass follows:
.....(1)
Let the fractional abundance of isotope be 'x'. So, fractional abundance of isotope will be '1 - x'
- <u>For isotope:</u>
Mass of isotope = 190.9606 amu
Fractional abundance of isotope = x
- <u>For isotope:</u>
Mass of isotope = 192.9629 amu
Fractional abundance of isotope = 1 - x
Average atomic mass of iridium = 192.22 amu
Putting values in equation 1, we get:
Percentage abundance of isotope =
Percentage abundance of isotope =
Hence, the percentage abundance of and isotopes are 37.10% and 62.90% respectively.