Answer : The atomic mass of the element is, 58.70 amu
Explanation :
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:
[tex]\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i[/tex]
As we are given that,
Percentage abundance of isotope A = 67.76 %
Fractional abundance of isotope A = 0.6776
Percentage abundance of isotope B = 26.16 %
Fractional abundance of isotope B = 0.2616
Percentage abundance of isotope C = 1.25 %
Fractional abundance of isotope C = 0.0125
Percentage abundance of isotope D = 3.66 %
Fractional abundance of isotope D = 0.0366
Percentage abundance of isotope E = 1.16 %
Fractional abundance of isotope E = 0.0116
Now put all the given values in above formula, we get:
[tex]\text{Average atomic mass}=[(57.93\times 0.6776)+(59.93\times 0.2616)+(60.93\times 0.0125)+(61.93\times 0.0366)+(63.93\times 0.0116)][/tex]
[tex]\text{Average atomic mass}=58.70amu[/tex]
Therefore, the atomic mass of the element is, 58.70 amu