Atomic Mass of Candium

Purpose:

• To use a Candium model to explain the concept of atomic mass.
• To analyze the isotopes of Candium and calculate its atomic mass.

Materials:

• Sample of Candium
• Balance

Procedure:

1. Obtain sample of Candium.
2. Separate it into its 3 isotopes.
3. Determine the total mass or each isotope.
4. Count the numbers of each isotope.
5. Record data and calculations in the data table.
6. Create a data table that has the following:
1. average mass of each isotope
2. percent abundance of each isotope
3. relative abundance of each isotope
4. relative mass of each isotope
5. average mass of all isotopes

	Sixlets	M&M’s	Skittles	Gobstoppers
Average Mass	0.81	0.87	1.08	1.67
Percent Abundance	0.32	0.26	0.21	0.19
Relative Abundance	15	12	10	9
Relative Mass	1.33	1.07	1	2.06
Average Mass	1.11	1.11	1.11	1.11

Discussion:

1. Summarize what you did.
2. Define the term isotope.
3. Explain the difference between percent abundance and relative abundance.
4. Compare the total values for rows 3 and 6 in the data table. How does the average mass differ from the relative mass?
5. Compare your value for relative mass to that of the class.
6. Comment on your percent error, sources of error in the activity, and provide suggestions for improvement.
7. Comment on how the activity is a model for calculating atomic mass of real elements.

Conclusion: