1. What is Average Atomic Mass?

The average atomic mass is the weighted average of the atomic masses of all naturally occurring isotopes of an element, taking into account their relative abundances. This is the value you see on the periodic table for each element.

2. How Does the Calculator Work?

The calculator uses the average atomic mass formula:

Where:

• Abundance — Natural abundance percentage of each isotope
• Isotope Mass — Mass of each isotope in atomic mass units (amu)

Explanation: The equation calculates a weighted average where more abundant isotopes contribute more to the final average mass.

3. Importance of Average Atomic Mass

Details: The average atomic mass is crucial for chemical calculations including stoichiometry, molar mass determinations, and understanding chemical behavior of elements.

4. Using the Calculator

Tips: Enter the mass of each isotope in amu and their natural abundance percentages. The abundances must sum to exactly 100%.

5. Frequently Asked Questions (FAQ)

Q1: Why don't abundances always sum to exactly 100%?
A: In reality, they do sum to 100%, but reported values may have rounding errors. For precise calculations, use exact values.

Q2: Can I calculate with more than two isotopes?
A: Yes, the same formula applies. Just add more (abundance × mass) terms to the numerator.

Q3: Why is average atomic mass not a whole number?
A: It's a weighted average of different isotope masses, which themselves often aren't whole numbers due to nuclear binding energy.

Q4: How accurate are these calculations?
A: Very accurate when using precise isotope masses and abundances. Results are typically reported to 4 decimal places.

Q5: Does this work for radioactive elements?
A: Yes, but abundances may vary in samples depending on origin and age due to radioactive decay.