Chemistry

Question Analysis
This question involves calculating the average atomic mass of an element using the masses and relative abundances of its three isotopes.
The main focus is on applying the weighted average formula to isotope data.

Key Concept Explanation
Average atomic mass = (mass of isotope 1 × % abundance₁/100) + (mass of isotope 2 × % abundance₂/100) + (mass of isotope 3 × % abundance₃/100)
It is a weighted average, accounting for the natural abundance of each isotope (not a simple arithmetic mean).

Step-by-step Solution
1. Convert the percent abundances to decimals: 75% = 0.75, 15% = 0.15, 10% = 0.10.
2. Use the formula for atomic mass: Average Atomic Mass = (Mass₁ × %Abundan...