1. What is Weighted Average Atomic Mass?

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

2. How Does the Calculator Work?

The calculator uses the weighted average formula:

Where:

• \( \text{abundance} \) — Natural abundance of the isotope (%)
• \( \text{isotope} \) — Atomic mass of the isotope (amu)
• \( \sum \) — Sum of all isotope contributions

Explanation: The equation accounts for the contribution of each isotope based on how common it is in nature.

3. Importance of Atomic Mass Calculation

Details: Accurate atomic mass is crucial for chemical calculations, stoichiometry, and understanding element properties. It affects molecular weight calculations and reaction yields.

4. Using the Calculator

Tips: Enter at least one isotope mass and its abundance. You can enter up to three isotopes. Abundance values should ideally sum to 100% for natural samples.

5. Frequently Asked Questions (FAQ)

Q1: Why don't my abundance values add up to 100%?
A: The calculator normalizes the calculation based on the entered abundances. For natural samples, they should sum to 100%.

Q2: What is amu?
A: Atomic mass unit (amu), now called unified atomic mass unit (u), is 1/12 the mass of a carbon-12 atom.

Q3: How many isotopes can I enter?
A: The calculator supports up to three isotopes, though most elements have fewer naturally occurring isotopes.

Q4: Why are atomic masses not whole numbers?
A: Atomic masses account for both protons+neutrons and the small mass contributions from electrons and nuclear binding energy.

Q5: Can I use this for radioactive elements?
A: For elements with radioactive isotopes, use only stable isotopes and their natural abundances.