## Chemistry 10th Edition

Atomic mass of Strontium = $87.6166amu$
Mass of Isotope 1 = $83.9134 amu$ % abundance of Isotope 1 = $0.56\%$ Mass of Isotope 2 = $85.9094 amu$ % abundance of Isotope 2 = $9.86\%$ Mass of Isotope 3 = $86.9089 amu$ % abundance of Isotope 3 = $7.00\%$ Mass of Isotope 4 = $87.9056 amu$ % abundance of Isotope 4 = $82.58\%$ Atomic mass of an element is the weighted average of the masses of its constituent isotopes. We convert the % abundance of each Isotope into fractions. Hence, Atomic mass of Strontium = $0.0056(83.9134amu)+0.0986(85.9094amu)+0.0700(86.9089amu)+0.8258(87.9056amu)$ Atomic mass of Strontium = $87.6166amu$