# Atomic Structure Calculating Average Atomic Mass Average Atomic

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Atomic Structure Calculating Average Atomic Mass

Average Atomic Mass Weight underneath each element on the periodic table is an average of all the isotopes that exist for that specific element 1 H 1. 0079 Hydrogen Isotopes of Hydrogen Mass of isotope (Relative Atomic Mass) Percent Abundance (%) Hydrogen – 1 1. 007825 99. 9885 Hydrogen – 2 2. 0141022 0. 0115 Hydrogen – 3 3. 016049 0. 003

Calculating Average Atomic Mass 1. Convert Percentages into DECIMALS These percentages are your percent abundance #’s To do this you need to Divide by 100 2. Multiply the percent abundance DECIMALS by its relative atomic mass 3. Add ALL the numbers from STEP 2 together

1. Convert Percentages into DECIMALS These percentages are your percent abundance #’s (Divide by 100) 2. Multiply the percent abundance DECIMALS by its relative atomic mass 3. Add ALL the numbers from STEP 2 together Naturally occurring copper is 69. 1% Cu-63 and 30. 9% Cu-65. What is the average atomic mass?

1. Convert Percentages into DECIMALS These percentages are your percent abundance #’s (Divide by 100) 2. Multiply the percent abundance DECIMALS by its relative atomic mass 3. Add ALL the numbers from STEP 2 together What is the average atomic mass of a sample of Neon with 90. 0% Neon-20 & 10. 0%Neon-22?

1. Convert Percentages into DECIMALS These percentages are your percent abundance #’s (Divide by 100) 2. Multiply the percent abundance DECIMALS by its relative atomic mass 3. Add ALL the numbers from STEP 2 together Calculate the average atomic weight for carbon from the following isotopic information: 98. 892% Carbon-12 and 1. 108% Carbon-13