Question

If an element consists of 60.10% atoms with mass 68.926 u and 39.90% atoms with mass 70.925 u, what is the atomic mass of the element?

Answer 1

To calculate the atomic mass of an element based on the percentage abundance of its isotopes, you can use the following formula:

Atomic mass = (Abundance of isotope 1 × Mass of isotope 1) + (Abundance of isotope 2 × Mass of isotope 2) + ...

Given the information you provided:

• Isotope 1: Abundance = 60.10%, Mass = 68.926 u
• Isotope 2: Abundance = 39.90%, Mass = 70.925 u

Let's substitute these values into the formula to calculate the atomic mass:

Atomic mass = (0.6010 × 68.926) + (0.3990 × 70.925) = 41.417426 + 28.317075 = 69.734501

Therefore, the atomic mass of the element is approximately 69.734 u.