Answer:
Option B. 28.5 amu
Explanation:
The following data were obtained from the question:
Isotope A:
Mass of A = 28.0 amu
Abundance (A%) = 14.0%
Isotope B:
Mass of B = 29.0 amu
Abundance (B%) = 66.0%
Isotope C:
Mass of C = 27.4 amu
Abundance (C%) = 20.0%
Atomic mass of element X =.?
The atomic mass of element X can be obtained by using the following formula:
Atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100]
Atomic mass of Element X = [(28 × 14)/100] + [(29 × 66)/100] + [(27.4 × 20)/100]
= 3.92 + 19.14 + 5.48
= 28.54 ≈ 28.5 amu
Therefore, the atomic mass of Element X is 28.5 amu
