Answer: average atomic mass of the element is 35.4536 amu and the element is chlorine.
Explanation:
Mass of isotope 1 = 34.969
% abundance of isotope 1 = 75.77% = [tex]\frac{75.77}{100}=0.7577[/tex]
Mass of isotope 2 = 36.965
% abundance of isotope 2 = (24.23)% = [tex]\frac{24.23}{100}=0.2423[/tex]
Formula used for average atomic mass of an element :
[tex]\text{ Average atomic mass of an element}=\sum(\text{atomic mass of an isotopes}\times {\text{ fractional abundance}})[/tex]
[tex]\text{ Average atomic mass of an element}=\sum[34.969\times 0.7577)+36.969\times 0.2423][/tex]
[tex]\text{ Average atomic mass of an element}=35.4536amu[/tex]
Therefore, the average atomic mass of the element is 35.4536 amu and the unknown element will be Chlorine.
