Name: ______________________
Atomic Theory
Discovering The Structure of The Atom
Station 1 - Vocabulary Map
Task: Look up the following words in the textbook and complete each portion of the vocab map.
Definition:
Picture:
Electrons
Sentence:
Definition:
Picture:
Proton
Sentence:
Definition:
Picture:
Nucleus
Sentence:
Definition:
Picture:
Neutron
Sentence:
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Name: ______________________
Atomic Theory
Discovering The Structure of The Atom
Station 2 – Mini Lab: Evidence for the Law of Definite Proportion
Task: Complete the following experiment and answer the questions that follow.
Materials: Balance, beans, paperclips, 2 cups (labeled “1” and “2”).
Each cup contains beans & paperclips in a predetermined amount. The beans & paperclips from each
cup should be weighed separately, do not combine the beans & paperclips from Cup 1 with the beans &
paperclips from Cup 2.
1. Use a balance to find the total mass of the beans in Cup 1. Mass of beans (Cup 1) = ________
2. Use a balance to find the total mass of the paperclips in Cup 1. Mass of paperclips (Cup 1) =________
3. Use a balance to find the total mass of the beans in Cup 2. Mass of beans (Cup 2) = ________
4. Use a balance to find the total mass of the paperclips in Cup 2. Mass of paperclips (Cup 2) =________
QUESTIONS
1. Based on your evidence, do you think that different substances could be made up of the same
elements, just different proportions? Explain. _________________________________________
______________________________________________________________________________
2. What law does this evidence support? ________________________________________________
Station 3 – Timeline Research
Task: Research to find the following information.
When did Democritus develop his atomic theory? ______________
What did Democritus suggest? ___________________________________________________________
What does the word indivisible mean? _____________________________________________________
Did everyone support Democritus’s theory? _________ Why or why not? _________________________
_____________________________________________________________________________________
When did Dalton develop his atomic theory? ________________
What did Dalton’s Atomic Theory say? _____________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
What law is used as evidence to support Dalton’s theory? ______________________________________
When did Thomson develop his atomic theory? ______________
What instrument did Thomson use to develop his theory? _____________________________________
How was Thomson’s model different from Dalton’s model of the atom? __________________________
What was Thomson’s model called? ________________________________
What did Rutherford say about the structure of the atom? _____________________________________
_____________________________________________________________________________________
What was Rutherford’s experiment called? __________________________________________________
As a result of his experiment, what did Rutherford discover? ___________________________________
When did Bohr develop his theory? ________________
What does Bohr’s theory say? ____________________________________________________________
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Name: ______________________
Atomic Theory
Discovering The Structure of The Atom
Station 4 - Timeline
Task: Using the information from your research, complete the timeline to show the development of the
atomic theory.
The timeline should include
 The following scientist: Democritus, John Dalton, JJ Thomson, Ernest Rutherford, and Niels Bohr
 The date,
 A description of their major contributions,
 An illustration of the model of the atom at that specific date.
Atomic Theory Timeline
1911
Summary: Describe how scientific knowledge is open to change as new evidence is observed.
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
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Name: ______________________
Atomic Theory
Discovering The Structure of The Atom
Station 5 – Read, Discuss, Write (Textbook Resource: Holt Science Spectrum)
Task: Read the following paragraphs, and complete the exercises below.
Seeing Atoms: The STM
The idea that everything is made up of small particles called atoms was first proposed by Greeks in the
fifth century BCE. At that time, there was no experimental evidence to support this theory, and it did not
gain much acceptance.
Much later, in the early 1800s, British scientist John Dalton made a convincing argument, based on
experimental evidence that supported the existence of atoms. Atoms are much too small to see, but
Dalton found evidence for them in things he could observe, such as reactions between compounds.
Because of the work of Dalton and others, the atomic theory soon became widely accepted by scientists.
How the STM Sees Atoms
Until recently, all evidence for the atomic theory was indirect. However, an exciting development in
1981 made it possible to see atoms for the first time. This new technology, the scanning tunneling
microscope (STM), uses an electric current to probe the surface of a material. The STM measures how
electrons are distributed on the material’s surface. The results are used to create a computer generated
image of the atoms on the surface.
The first image created by an STM showed a layer of gold atoms. Since then, the atoms of many
different substances have been observed with STMs, including silver, nickel, platinum, and silicon. At
this time, STMs are used primarily for imaging atoms. STMs have also been used to move single atoms
from one location to another, and other potential applications are being researched.
EXERCISES – Discuss the answers to the following questions then, on your own, write your response.
1. What is the most important difference between the Greek theory of atoms and Dalton’s atomic
theory?
_____________________________________________________________________________________________________
___________________________________________________________________________________________________
2.What is the significance of the invention of the STM?
Station 6 – Creation Station: Model the Development of the Atomic Theory
Task: Use the items provided to build Dalton’s model of the atom, J.J. Thomson’s model of the atom,
Rutherford’s model of the atom, and Bohr’s model of the atom then answer the following questions.
Materials: Modeling clay (several colors)
Questions
1. Compare Thomson’s atomic model with Rutherford’s atomic model. Explain how they are the
same and how they are different.
______________________________________________________________________________
______________________________________________________________________________
2. Does the term indivisible still describe the atom? Explain.
______________________________________________________________________________
______________________________________________________________________________
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Name: ______________________
Atomic Theory
Discovering The Structure of The Atom
Station 7 – The Structure of Atoms
Task: Examine the diagram and think about the discoveries that each scientist made to develop the
atomic theory to answer the following questions.
1. What is the center of the atom called? _____________
2. The center of the atom is made up of positively charged particles and
particles that have no electrical charge. Name the two particles.
Particles with a positive charge = _____________________
Particles with no charge = ___________________________
3. Negatively charged electrons are found in clouds outside the center of
an atom. Why are electrons attracted to the center of the atom?
__________________________________________________________
__________________________________________________________
Extension:
Use the items provided to build a model of a neutral Carbon atom. Draw your model (be sure to label
what each color represents) & explain it when you’re done.
Materials: 1 bowl, 30 balls (10 red, 10 yellow, 10 black), colored pencils (red, yellow, black), periodic
table
Draw
Red represents ____________________.
Yellow represents __________________.
Black represents ___________________.
How many protons did you use? _______
How many neutrons did you use? ______
How many electrons did you use? ______
What does the bowl represent?
___________________________________
Explain where you placed your subatomic particles and why you placed them in that location.
_____________________________________________________________________________________
_____________________________________________________________________________________
How did you select the amount of protons, neutrons, and electrons that you chose to use?
_____________________________________________________________________________________
_____________________________________________________________________________________
© Copyright 2014 – all rights reserved www.cpalms.org
Name: ______________________
Atomic Theory
Discovering The Structure of The Atom
Stations 8 – Lab Simulator: Build an Atom (Online Resource: phet.colorado.edu)
Task: Complete the lab simulator to answer the following questions.
1. Google Phet Build an Atom
2. Click on the first link.
3. Click on the RUN NOW button
4. Open the boxes called Symbol, Mass Number, and Net Charge.
5. Experiment by putting some protons into the nucleus of the atom (on the X).
Fill in the table to the right to keep
track of what you are learning
about protons.
Mass
Charge?
number?
Symbol changes on
the center
the periodic table?
(on the
X)?
When you finish, put the protons
back into the bowl.
6. Experiment by putting some neutrons
into the nucleus of the atom (on the X).
Fill in the table to the right to keep
track of what you are learning
about neutrons.
Stays in
Mass
Charge?
number?
Yes or No
Yes or No
Stays on
Symbol changes on
the X?
the periodic table?
Yes or No
When you finish, put the neutrons
back into the bowl.
Yes or No
7. Experiment by putting some electrons into the nucleus of the atom (on the X).
Fill in the table to the right to keep
track of what you are learning
about electrons.
When you finish, put the electrons
back into the bowl.
Mass
number?
Charge?
Stays on
Symbol changes on
the X?
the periodic table?
Yes or No
Yes or No
8. Look over your data tables for protons, neutrons and electrons.
Two things we noticed are: 1. _________________________________________________
2. _________________________________________________
9. Put 3 protons into nucleus of the atom. Fill in the following:
Name of atom:___________
atom or ion? _________ net charge? _________
10. Decide how you will build a neutral atom that is stable. Practice making atoms using your ideas.
List the steps that youwould take to build a neutral atom starting with protons:
1. First I choose _______ protons and put them in the center (nucleus) of the atom.
2.
3.
Extension: Play the game!
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