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Average Atomic Mass Formula:
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The average atomic mass is the weighted average of the atomic masses of all naturally occurring isotopes of an element. It takes into account both the mass and relative abundance of each isotope.
The calculator uses the average atomic mass formula:
Where:
Explanation: The formula calculates the weighted average where each isotope's contribution is proportional to its natural abundance.
Details: Average atomic mass is crucial for chemical calculations, stoichiometry, and understanding the composition of elements as they occur naturally. It's the value shown on the periodic table for each element.
Tips: Enter the mass of each isotope in amu and their fractional abundances (values between 0 and 1). The sum of abundances should equal 1 for accurate results.
Q1: Why is average atomic mass not a whole number?
A: Because it's a weighted average of different isotopes with different masses, taking into account their natural abundances.
Q2: What's the difference between atomic mass and mass number?
A: Mass number is the total number of protons and neutrons in a specific isotope (always a whole number), while atomic mass is the weighted average of all naturally occurring isotopes.
Q3: How many isotopes can this calculator handle?
A: This calculator handles two isotopes. For elements with more isotopes, the calculation would include additional terms in the sum.
Q4: Why do abundances need to be fractions?
A: Using fractional abundances (0-1) ensures the weighted average calculation is mathematically correct. Percent abundances would need to be converted to fractions (divided by 100).
Q5: Are there elements with only one naturally occurring isotope?
A: Yes, some elements like fluorine, sodium, and aluminum have only one stable naturally occurring isotope.