<u>Answer:</u> The percentage abundance of and isotopes are 75.77% and 24.23% 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 = 62.9396 amu
Fractional abundance of isotope = x
- <u>For isotope:</u>
Mass of isotope = 64.9278 amu
Fractional abundance of isotope = 1 - x
- Average atomic mass of copper = 63.546 amu
Putting values in equation 1, we get:
Percentage abundance of isotope =
Percentage abundance of isotope =
Hence, the percentage abundance of and isotopes are 69.50% and 30.50% respectively.