1. Average Atomic Mass Practice
Silicon has 3 isotopes with the following % abundances.
Si-28, 92.23%
Si-29, 4.67%
Si-30, 3.10%
Calculate silicon’s average atomic mass.

2. Answer
(28 x ) + (29 x ) + (30 x .031) = amu

3. % Abundance Practice Silver, Ag, exists as 2 isotopes, Ag-107
and Ag Calculate the % abundance for each isotope of silver.

4. Answer
= (x)(107) + (1-x)(109) X= Ag-107 is 56.59% abundant Ag-109 is 43.41% abundant

5. 2) Lithium exists as 2 isotopes, Li-6 and Li-7
2) Lithium exists as 2 isotopes, Li-6 and Li-7. Calculate the % abundance for each isotope of lithium.

6. Answer
6.941=(x)(6) + (1-x)(7) X= Li-6 is 5.90% abundant Li-7 is 94.10% abundant