Question

Element X has two naturally occurring isotopes . Its first isotope has a mass of 28.0 amu and a natural abundance of 64.24%. Its second isotope has a mass of 25.0 amu. What is the atomic mass of element X?

Answer 1

m1=mass of 1st isotope

P1=%abundance of 1st isotope

m2=mass of 2nd isotope

p2=%abundance of 2nd istope

p2=100-64.24=35.76

$aam= \frac{28 \times 64.24+ 25 \times 35.76}{100} \\ aam = \frac{1798.72 + 894}{100} \\aam = \frac{2692.4}{100} = 26.9$Thank you...