<u>Answer:</u> The average atomic mass of Strontium is 87.65 u
<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)
- <u>For isotope:</u>
Mass of isotope = 85.91 u
Percentage abundance of isotope = 9.46 %
Fractional abundance of isotope = 0.09460
- <u>For isotope:</u>
Mass of isotope = 86.91 u
Percentage abundance of isotope = 7.00 %
Fractional abundance of isotope = 0.0700
- <u>For isotope:</u>
Mass of isotope = 87.91 u
Percentage abundance of isotope = 83.54 %
Fractional abundance of isotope = 0.8354
Putting values in equation 1, we get:
Hence, the average atomic mass of Strontium is 87.65 u