An element Y has three naturally occurring isotopes: Y-40 wi...

Question

An element Y has three naturally occurring isotopes: Y-40 with a mass of 39.96 amu and an abundance of 91.75%, Y-41 with a mass of 40.96 amu and an abundance of 6.73%, Y-42 with a mass of 41.96 amu and an abundance of 1.52%. The average atomic mass of element Y is _______ amu(Round to two decimal places).

Question Analysis
This question involves calculating the average atomic mass of an element with three isotopes.
The main focus is on applying the weighted average formula for multiple isotopes (mass × abundance for each isotope, then summing).

Key Concept Explanation
Average atomic mass = (Mass of isotope 1 × Abundance₁) + (Mass of isotope 2 × Abundance₂) + (Mass of isotope 3 × Abundance₃)
Abundances must be converted from percentages to decimals (divide by 100).

Step-by-Step Solution
1. Convert abundances to decimals:
Y-40: 91.75% = 0.9175
Y-41: 6.73% = 0.0673
Y-42: 1.52% = 0.0152
2. Calculate each isotope’s contribution:
Y-40: 39.96 amu × 0.9175 = 36.6...

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