Fe = 5 We have to find the relative atomic mass of Fe. Weight of any element is given by : Weight of element = Σ (Percentage abundance of isotope × Atomic mass of isotope) Thus, Weight of
54
Fe = 0.05 × 54 = 2.7 Weight of
56
Fe = 0.9 × 56 = 50.4 Weight of
57
Fe = 0.05 × 57 = 2.85 Now, Relative atomic mass of Fe = 2.7 + 50.4 + 2.85 = 55.95 Hence, option 'B' is correct