An element has four naturally occurring isotopes with the masses and natural abundances given here. find the atomic mass of the element. isotope mass (amu) abundance (%) 1 135.90714 0.1900 2 137.90599 0.2500 3 139.90543 88.43 4 141.90924 11.13

Abundance of each isotope = 0.1900 x100 = 0.001900

0.2500 = 0.002500

88.43 = 0.8843

11.13 = 0.1113

Atomic mass of the element = (135.90714 x 0.001900) + (137.90599 x 0.002500) + (139.90543 x 0.8843) + (141.90924 x 0.1113)

= 0.258223566 + 0.344764975 + 123.718371749 + 15.794498412

= 140.1 amu is the atomic mass of the element