Given that the abundance of isotopes is 5%, 90% and 5% respectively, the atomic mass of Fe is: [1] — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question

💡 Solution & Explanation

$\text{Average atomic mass} = \sum (\text{Isotopic mass} \times \text{Abundance})$. <br>$\text{Mass} = (54 \times 0.05) + (56 \times 0.90) + (57 \times 0.05) = 2.7 + 50.4 + 2.85 = 55.95$. [1]