1. What is Atomic Mass?

Atomic mass is the weighted average mass of all naturally occurring isotopes of an element, measured in atomic mass units (amu). It accounts for both the mass and relative abundance of each isotope.

2. How Does the Calculator Work?

The calculator uses the atomic mass formula:

Where:

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

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

3. Importance of Atomic Mass Calculation

Details: Atomic mass is fundamental in chemistry for stoichiometric calculations, determining molar masses, and understanding chemical reactions. It appears on the periodic table for each element.

4. Using the Calculator

Tips: Enter the mass of each isotope in amu and their natural abundances in percentage. The sum of abundances should not exceed 100%. For elements with more than two isotopes, calculate them in stages.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between atomic mass and mass number?
A: Mass number is the sum of protons and neutrons in a specific isotope (always a whole number), while atomic mass is the weighted average of all naturally occurring isotopes (usually a decimal).

Q2: Why are atomic masses on the periodic table not whole numbers?
A: They're weighted averages of all naturally occurring isotopes, which have different masses and abundances.

Q3: How precise should my inputs be?
A: For accurate results, use isotope masses to at least 4 decimal places and abundances to 2 decimal places.

Q4: What if an element has more than two isotopes?
A: You can chain calculations - first average two isotopes, then use that result with the third isotope, and so on.

Q5: Where can I find isotope mass and abundance data?
A: The IUPAC publishes comprehensive isotope data. Many chemistry textbooks and reputable online sources also provide this information.