NAME: _______________________________________
PARTNER’S NAME: __________________________
DATE DUE: ______________________ PER: _____
Chemistry Lab Report – Predicting the Location of a 1s Electron
Your lab report will consist of completing the attached packet. You may work as a group to
complete the Data and Analysis section but EACH person must turn in their own Conclusions and
Post Lab Questions.
Your lab report will be graded according to the following
Possible Student Points
Points Points Earned
I.
Name/Partner’s Name/Date Due/Period
II.
Data: Observations and/or measurements made during the activity
1. Data Table is complete with correct units
III.
IV.
`
Analysis: All work shown with correct units and sigfigs
1. Calculations for area of each ring
2. Calculations for dots per cm2
3. Graph of average distance from the center vs. number of dots
per cm2
4. Calculations for probability of finding dot in each ring
Conclusions & Post Lab Questions:
1. All questions are answered correctly
2. All questions are answered in complete sentences & have no
spelling or grammatical errors
TOTAL
2
.
5
.
5
5
.
.
5
5
.
.
10
.
5
.
42
.
Chemistry Lab – Predicting the Location of a 1s Electron
Problem: Where is a 1s electron most likely to be found?
Materials (per group): Section of newspaper, sheet of paper with target drawn on it, piece of tape,
pen/pencil
Procedure:
1. Using the target on the sheet of paper complete the data collection. The center of the target
represents the atom’s nucleus, which is very small in comparison to the rest of the atom. There are
5 concentric circles around the dot so that the radius of each circle is 2.0 cm greater than that of
the preceding circle.
2. Place a section of newspaper on the floor and tape the target to the paper so that it will not move.
3. Stand on the opposite side of the target from your partner. Holding a pen/pencil at shoulder height
above the center of the target, take turns dropping the pen/pencil so that it leaves a dot when it hits
the target. Aim for the center of the target. Each dot represents the location of an electron at
that moment.
4. Continue dropping the pen/pencil until you each have 50 “electron” dots on your target.
5. Count the number of dots in each ring and record that number in the data table below.
Data Table
Ring Number
Average Distance
From Center
1
2.0 cm
2
4.0 cm
3
6.0 cm
4
8.0 cm
5
10.0 cm
Area of Ring
Number of Dots
in Ring
Dots per cm2
Analysis:
1. Show calculations for area of each ring here:
2. Show calculations for dots per cm2 for each ring here:
3. On a separate sheet of graph paper, make a graph of your observations by plotting the average
distance from the center on the x-axis and the number of dots per cm2 on the y-axis. (Do not
forget to use T.A.I.L.S for the graphing)
4. Determine the probability of finding a dot in each of the rings in the target by dividing the number
of dots in the ring by the total number of dots that you and your partner made. Multiplying this
fraction by 100 will give you the percent probability. Show these calculations here:
BONUS +5
An atomic orbital is defined as the region within which an electron is found 90% of the time. On your
target, draw a circle within which 90% of the dots are found. Use a different color from the one you
used on the target. What is the distance of this circle from the center? What is the area of this circle?
Show all work here.
NAME: _______________________________
DATE: _______________ PER: ___________
Conclusions & Post Lab Questions – Answered in complete sentences.
1. What happens to the number of dots per unit area as the distance from the center increases?
2. Based on your graph, what is the distance with the highest probability of finding a dot? Explain
how you determined this answer.
3. Based on your calculations how many dots are actually located at the distance of highest
probability?
4. In an actual atom, will there necessarily be an electron at the distance with the highest probability
of finding an electron? Explain your answer.
5. What are two ways is this model is similar to the structure of an atom? What are two ways it is
different?
NAME: _______________________________
DATE: _______________ PER: ___________
Conclusions & Post Lab Questions – Answered in complete sentences.
1. What happens to the number of dots per unit area as the distance from the center increases?
2. Based on your graph, what is the distance with the highest probability of finding a dot? Explain
how you determined this answer.
3. Based on your calculations how many dots are actually located at the distance of highest
probability?
4. In an actual atom, will there necessarily be an electron at the distance with the highest probability
of finding an electron? Explain your answer.
5. What are two ways is this model is similar to the structure of an atom? What are two ways it is
different?