Name __________________________ Teacher _____________ Period ______Date ___________
Candium Isotope Lab TEKS C63d
Objective: Learn about isotopes and how to calculate the percent abundance and average atomic mass.
Pearce High School students were experimenting with sweet success when they discovered a new element,
Candium. They also discovered Candium naturally occurs as 3 different isotopes:
1) Candium-?, 2) Candium-?, 3) Candium-?.
The isotopic notation is listed incorrectly because the mass of each is yet to be discovered.
You will carry out experiments and perform the necessary calculations to determine the atomic mass of all of
the isotopes of the fictitious element Candium. As in real elements, these isotopes are a collection of particles
having different masses. Your job will be to obtain a sample of Candium and determine the relative abundance
of each isotope and the mass of each type of particle. From this data you will calculate the average atomic
mass of Candium. Unlike real isotopes, the individual isotopic particles of Candium look different.
On your lab table you have a container that holds a sample of Candium atoms.
 Each candy is an individual atom of the element Candium.
 Each different type of candy is a different isotope of the element.
The isotopes (different types of candies) of this element have different masses just like real isotopes.
In this lab, you will calculate the average atomic mass of your sample of Candium.
Purpose:
To determine _____________________________________________________________________________
Pre Lab Questions:
1. What does each Candy represent? _______________________________________________
2. What does each type of Candy represent? _________________________________________
3. What does the different masses of the candies represent? ____________________________
4. A student collected the following data when measuring a Candium sample:
Type of
Candy
# of Candies
(atoms)
Total Mass of
Isotope (g)
Candy A
162
61.052 g
Candy B
181
54.126 g
Candy C
292
59.784 g
Atomic Mass(g)
(single candy)
Fractional
Abundance
%
Abundance
Average
Atomic Mass
Calculate the following and record in the above table:
a) atomic mass of a single Candy of each isotope
b) fractional abundance of each isotope
c) % abundance of each isotope
d) Weighted average atomic mass of each isotope
e) average atomic mass of this sample of Candium
Candium Lab
Weighted
Average
Name __________________________ Teacher _____________ Period ______Date ___________
Data Table
A
B
C
D
E
F
G
H
Isotope of
Candium
Isotope
Description
Atomic
Mass
(in grams)
%
Abundance
Weighted
Average
Candy
Name
Total Mass
of Isotope
(in grams)
Fractional
Abundance
Isotopic
Notation
# of
Candies
(atoms)
(single candy)
1)
%
2)
%
3)
%
Total # of all Candies
I
Total mass of all
Candies
Total should=100%
J
Average
Atomic
Mass
K
Procedure:
1. Separate the candies into the different types. Each group represents a different isotope. Record the
number of candies (atoms) of each isotope in column (C) and the total number of all of the candies in box I.
2. Find the total mass of each isotope using the balance and record in column (D) and the total mass of all of
the candies in box J.
Data Analysis: Show all work, by numbered questions, on the back of this lab report. Remember sig figs.
1. Divide the total mass of each isotope (D) by the number of atoms (C) in that particular isotope to find the
mass (on average) of a single atom of that isotope and record in column (E).
This is the atomic mass of that isotope.
Total Mass of Isotope
# of Candies (atoms)
2. Determine the fractional abundance (F) of each isotope by dividing the number of atoms of that isotope (C)
by the total number of atoms (I) present in your sample and record in column F
# of candies (atoms) of this Isotope
Total # of candies (atoms) in sample
3. Determine the % abundance (G) by multiplying the fractional abundance of each isotope by 100
for each isotope.
4.
Determine the weighted average atomic mass (H) of each isotope by multiplying the atomic mass
(E) of the isotope by the fractional abundance (F).
Atomic Mass X Fractional Abundance
5.
Find the Average Atomic Mass (K) of Candium by adding the weighted averages (H) of all of the
isotopes together and recording this in box K.
Candium Lab
Name __________________________ Teacher _____________ Period ______Date ___________
Post Lab Questions:
1. What property of Candium distinguishes each of its isotopes? (not color)
2. Which isotope is most abundant in your sample of Candium?
3. Look at your average atomic mass. Which isotope is it closest to?
4. Create a periodic table tile for your Candium element listing the atomic number and average
atomic mass and creating an appropriate elemental symbol that has not been used on the
periodic table. Complete the list:
Atomic Number=
Average Atomic Mass=
# of protons=
Mass #=
# of electrons if neutral=
AZ Notation=
# of neutrons=
Isotopic Notation=
Relate to the Real World:
1. What is the equation to find the average atomic mass of a real element.
2. Explain why it is important to use the weighted average of isotopes when finding the average
atomic mass of an element.
3. Explain why most element’s average atomic mass are not whole numbers.
4. Explain how 3 isotopes of hydrogen (H-1, H-2, H-3) are alike and different.
Alike
Different
5. Copper has 2 isotopes, Copper-63 and Copper-65. The percent abundance of C-63 is 69.1%
and C-65 is 30.9%. Find the average atomic mass of Copper.
Conclusion: Write a 3 sentence CER Conclusion on the back of the lab repot
Claim: (Hypothesis)
Evidence: (Observations, Procedure, Data)
Reason: (Accept or Reject Hypothesis, Link Claim to Data with reasoning)
Extension: What do you need to do to find the isotopic composition of Pennium?
After remaining virtually unchanged since it was first issued in 1909, in 1982 the Lincoln Head penny lost a full 20% of its mass. The change
was made as an economy measure. The mass loss was due to the partial substitution of less expensive and lower density zinc for the
original copper. Copper prices had risen to the point at which the metal in the penny was worth more than one cent. When the material value
of a coin becomes greater than its face value, two undesirable things can happen. First, the U.S. Treasury begins to lose money in
manufacturing the coin. (When the content of the penny was changed in 1982, it was estimated that the United States would save $25-$50
million annually.) Second, individuals may remove the coins from circulation to sell them for their metal content.
Chemists are often called upon to find ways to substitute less costly, more plentiful resources for scarce and expensive ones. The old penny
was 95% copper and 5% zinc. The new penny is 97.6% zinc, coated with a thin electroplating of copper. It is almost as durable as the old
penny, since the strong copper plating protects the more chemically reactive zinc from the wear and tear of daily use. As you might suspect,
the pre-1982 penny and post-1982 pennies have different masses as well as different compositions. In this laboratory activity, a mixture of
these pennies will represent the naturally occurring mixture of two isotopes of the imaginary element, “Pennium.” With the pennies, you will
simulate one way that scientists can determine the relative amounts of different isotopes present in a sample of an element.
Candium Lab
Name __________________________ Teacher _____________ Period ______Date ___________
Candium Isotope Lab TEKS C63d
Objective: Learn about isotopes and how to calculate the percent abundance and average atomic mass.
Pearce High School students were experimenting with sweet success when they discovered a new element,
Candium. They also discovered Candium naturally occurs as 3 different isotopes:
1) Candium-?, 2) Candium-?, 3) Candium-?.
The isotopic notation is listed incorrectly because the mass of each is yet to be discovered.
You will carry out experiments and perform the necessary calculations to determine the atomic mass of all of
the isotopes of the fictitious element Candium. As in real elements, these isotopes are a collection of particles
having different masses. Your job will be to obtain a sample of Candium and determine the relative abundance
of each isotope and the mass of each type of particle. From this data you will calculate the average atomic
mass of Candium. Unlike real isotopes, the individual isotopic particles of Candium look different.
On your lab table you have a container that holds a sample of Candium atoms.
 Each candy is an individual atom of the element Candium.
 Each different type of candy is a different isotope of the element.
The isotopes (different types of candies) of this element have different masses just like real isotopes.
In this lab, you will calculate the average atomic mass of your sample of Candium.
Purpose:
To determine _____________________________________________________________________________
Pre Lab Questions:
5. What does each Candy represent? _______________________________________________
6. What does each type of Candy represent? _________________________________________
7. What does the different masses of the candies represent? ____________________________
8. A student collected the following data when measuring a Candium sample:
Type of
Candy
# of Candies
(atoms)
Total Mass of
Isotope (g)
Candy A
162
61.052 g
Candy B
181
54.126 g
Candy C
292
59.784 g
Atomic Mass(g)
(single candy)
Fractional
Abundance
%
Abundance
Average
Atomic Mass
Calculate the following and record in the above table:
f) atomic mass of a single Candy of each isotope
g) fractional abundance of each isotope
h) % abundance of each isotope
i) Weighted average atomic mass of each isotope
j) average atomic mass of this sample of Candium
Candium Lab
Weighted
Average
Name __________________________ Teacher _____________ Period ______Date ___________
Data Table
A
B
C
D
E
F
G
H
Isotope of
Candium
Isotope
Description
Atomic
Mass
(in grams)
%
Abundance
Weighted
Average
Candy
Name
Total Mass
of Isotope
(in grams)
Fractional
Abundance
Isotopic
Notation
# of
Candies
(atoms)
(single candy)
1)
%
2)
%
3)
%
Total # of all Candies
I
Total mass of all
Candies
Total should=100%
J
Average
Atomic
Mass
K
Procedure:
3. Separate the candies into the different types. Each group represents a different isotope. Record the
number of candies (atoms) of each isotope in column (C) and the total number of all of the candies in box I.
4. Find the total mass of each isotope using the balance and record in column (D) and the total mass of all of
the candies in box J.
Data Analysis: Show all work, by numbered and letter box from the data table, on the back of this lab report.
Remember sig figs.
Post Lab Questions:
6. What property of Candium distinguishes each of its isotopes? (not color)
7. Which isotope is most abundant in your sample of Candium?
8. Look at your average atomic mass. Which isotope is it closest to?
9. Why is the element Candium a good analogy or model for an actual element isotope? In what
way is this analogy misleading or incorrect?
10. Create a periodic table tile for your Candium element listing the atomic number and average
atomic mass and creating an appropriate elemental symbol that has not been used on the
periodic table. Complete the list:
Atomic Number=
# of protons=
# of electrons if neutral=
# of neutrons=
Average Atomic Mass=
Mass #=
AZ Notation=
Isotopic Notation=
Candium Lab
Name __________________________ Teacher _____________ Period ______Date ___________
Relate to the Real World:
11. What is the equation to find the average atomic mass of a real element.
12. Explain why it is important to use the weighted average of isotopes when finding the average
atomic mass of an element.
13. Explain why most element’s average atomic mass are not whole numbers.
14. Explain how 3 isotopes of hydrogen (H-1, H-2, H-3) are alike and different.
Alike
Different
15. Copper has 2 isotopes, Copper-63 and Copper-65. The percent abundance of C-63 is 69.1%
and C-65 is 30.9%. Find the average atomic mass of Copper.
Conclusion: Write a 3 sentence CER Conclusion
Claim: (Hypothesis)
Evidence: (Observations, Procedure, Data)
Reason: (Accept or Reject Hypothesis, Link Claim to Data with reasoning)
Extension: What do you need to do to find the isotopic composition of Pennium?
After remaining virtually unchanged since it was first issued in 1909, in 1982 the Lincoln Head penny lost a full 20% of its mass. The change
was made as an economy measure. The mass loss was due to the partial substitution of less expensive and lower density zinc for the
original copper. Copper prices had risen to the point at which the metal in the penny was worth more than one cent. When the material value
of a coin becomes greater than its face value, two undesirable things can happen. First, the U.S. Treasury begins to lose money in
manufacturing the coin. (When the content of the penny was changed in 1982, it was estimated that the United States would save $25-$50
million annually.) Second, individuals may remove the coins from circulation to sell them for their metal content.
Chemists are often called upon to find ways to substitute less costly, more plentiful resources for scarce and expensive ones. The old penny
was 95% copper and 5% zinc. The new penny is 97.6% zinc, coated with a thin electroplating of copper. It is almost as durable as the old
penny, since the strong copper plating protects the more chemically reactive zinc from the wear and tear of daily use. As you might suspect,
the pre-1982 penny and post-1982 pennies have different masses as well as different compositions. In this laboratory activity, a mixture of
these pennies will represent the naturally occurring mixture of two isotopes of the imaginary element, “Pennium.” With the pennies, you will
simulate one way that scientists can determine the relative amounts of different isotopes present in a sample of an element.
Candium Lab