Science: Chemistry
Unit: Atomic History and Structure
Objectives: 2.01 & 2.02
Total Time: 120 minutes (Some tasks can be assigned as homework to reduce classroom time)
Essential Question: How have the experiments of various scientists affected the atomic theory
over time?
 Engage (10 minutes)
Mystery Bags:
o Materials: brown paper bags; several small objects that can be identified by
properties other than sight. Possible objects include lemon slices (odor), pennies
(shape), rubber bands (Elasticity), sandpaper squares (texture), and bells (sound).
o Activity: The purpose of this activity is for students to make inferences, based on
their observations and conclude that indirect evidence must be used to study the
structure of objects that are too small to see. Students should also recognize that
detailed observations can reveal information about objects and events that
cannot be observed directly. (See procedure below)
o Note: one type of object can be placed in a bag or several types of objects can be
placed in a bag. In either case, the brown paper bags should be sealed.
Alternative:
o Ask students whether they have ever attempted to guess the contents of a
wrapped gift. Have them discuss or write how they used inferences to get clues
and how gift-guessing might be similar to the reasoning used by atomic scientists
to determine atomic structure.
 Explore (20 minutes)
Introduction: Discuss atomic particles and the usefulness of scientific models
Models are less expensive to build than the actual item and they allow the study of things
that are difficult to visualize or duplicate.
Atomic Model Timeline
o Materials: “Evolution of the Atom” handout, Construction Paper, scissors, glue,
computer with internet access, averkey/lcd projector/smart board
o Give each student/group a sheet with pictures of each relevant atomic model
with the corresponding scientist (See “Evolution of the Atom” below)
o Students should cut out each model and predict the chronological order of the
atomic models
o Show the video clip entitled, “Atomic Model Brain Pop Movie” o As students watch the video clip, they should confirm or rearrange the order of
the atomic models
o At the end of the video clip, students should then paste the pictures of the
models on a piece of construction paper in chronological order(timeline) and
write down a characteristic that distinguishes each model from the previous
model
o Please note: The timeline can be done on an individual basis or in collaborative
small groups
 Elaborate ( 10 minutes)
Atomic Candy
o Materials – Assorted Candy (Suggestions – Blow pops, Kit-Kats, Snickers, gumballs)
o Students (or Each collaborative group) should select 5 different pieces of candy
o After each student has selected his or her candy, instruct the students match each
piece of candy to the atomic model.
o Students should record which candy was selected for each atomic model and write
an explanation/analogy of how the piece of candy is similar to the particular atomic
model
o Alternative materials: Sports equipment (basketball, tennis racket, etc.), small office
products (paperclips, safety pins, etc.), pictures of food, model or pictures of various
cars, etc.
 Explain (20 minutes)
History of the atom graphic organizer
o Teacher will guide students through the History of the Atom PowerPoint
Presentation and the “History of the atom” graphic organizer experiments
o Students will fill in blanks and sketch the various experiments and models
o Online Animation: This animation discusses Thomson’s model and the
Rutherford Gold Foil Experiment. It also explains and gives a visual of how
Rutherford’s expected results differed from his actual results.
 Elaborate (30 min)
o Option 1: Students will work in collaborative groups (group roles can include –
recorder, reporter, timekeeper, and facilitator) through the sheets explaining
each relevant experiment. Each collaborative group should be responsible for
reviewing a portion of the experiment with the entire class
 The Dalton Model
 Understanding the Rutherford Model
o Option 2: Lab - Discovering charged particles within the atom
o Extension: Students can create a model to “recreate” one of the scientist’s
experiments
 Evaluate (30 min )
o Student Generated Quizzes
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Students should work in collaborative groups and use Marzano Levels of
Thinking question stems to generate 10 questions (with answers) related
to the development of the atomic theory. (See template below)
Students groups can then challenge other student groups by asking quiz
questions to other groups.
o Project: Students will create a product that includes all of the key scientists
involved in the evolution of the atomic theory, the corresponding model, and
their contributions. Projects can be done outside of class individually or in
groups. Time for presentations can be incorporated into class time after the
project due date. Suggested product options are as follows:
 Children’s book: Students will make a CREATIVE Children’s book or comic
strip explaining what an atom is and how it has evolved over time. The book or
comic strip should be written so that an elementary school student can
understand its content.
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Atomic Biography: Have students write a narrative describing the
changes in the atomic model through time from the perspective of the
atom
Talk Show: Each group can become an expert on one of the atomic
theory scientists and serve on a “atomic model” panel
Historical Role Play: Students can act out an experiment or conversation
by an atomic scientist or debate between the various scientists defending
their atomic models
Debate/Persuasive Essay – Student will select one of the scientists who
contributed to the atomic theory and defend why this scientist’s
contribution was the most significant
 Links on Persuasive Writing
o http://www.writeexpress.com/persuasive-essay.html
o http://www.orangeusd.k12.ca.us/yorba/persuasive_writ
ing.htm
Other suggestions include: mneumonic devices, story, interview with the
atom, newspaper story, 3-d models, atomic mobile, newscast, poem, rap,
song, essay, time line, website, PowerPoint
Mystery Bags
Procedure:
1. Make and record observations about the contents of the
sealed brown paper bags provided by your teacher. Use
your senses of touch, smell, and hearing to help you make
your observations.
2. Based on your observations, predict what objects could be
in each bag. Decide whether there is a single object or
more than one object in each bag.
Data Table:
Bag Number
Observations
Analysis:
1. What evidence did you use to predict what objects were in the bags and how many
objects were in the bags?
2. Propose an experiment that could test one of your predictions.
3. Infer how the skills used in this activity could be applied to the study of atoms.
Bloom’s & Marzano’s
LEVELS OF THINKING
Elevate your thinking!
Levels
Evaluating
Integrating /
Synthesis
Generating
Analyzing
Applying
Organizing /
Comprehension
Knowing
Associated Verbs
Judge
Evaluate
Rate
Verify
Assess
Define Criteria
Combine
Summarize
Design
Imagine
Generalize
Conclude
Predict
Infer
Explain
Elaborate
Outline
Diagram
Differentiate
Analyze
Apply
Make
Show
Record
Construct
Demonstrate
Illustrate
Categorize
Group
Classify
Compare / Contrast
Interpret
List
Name
Label
Recall
Identify
Match
Choose
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Question Stems
How would you prove…? disprove…?
What would you cite to defend the actions…?
How would you prioritize…?
What information would you use to support the
view…?
Which … is most significant and why?
Judge what would be the best way to…?
Design a plan for ….
How would you summarize…?
What generalizations can you make about…?
How would you adapt to …to create a different…?
Can you predict the outcome if …?
How many ways can you think of …?
What would happen if…?
Elaborate about….
What solutions would you suggest for …?
What are the attributes of…?
What patterns or relationships do you see?
What are the main ideas of…?
Can you diagram, web or map this idea?
What are the different parts of…?
How is …related to…?
How is … an example of …?
How would you use this information to…?
What do you need to solve this problem?
How would you organize … to show…?
How would you apply what you learned to
develop…?
Categorize …according to….
Classify … according to….
How is … alike or different from …?
What is most or least important about…?
How would you rephrase the meaning of …?
What is…?
How did … happen or occur?
Who did…?
Identify the … and ….
Which … best describes…?
Which … is an example of …?
What best defines…?
Student Generated Quiz: (Sample)
Atomic Structure & History
Create a 10 question quiz related to Atomic Structure & History. You must use a question stem from each level of
thinking on the Marzano chart provided for you. You must also attach an answer key to your quiz. You may just
see your questions on our next quiz or test!
No.
1
Level of Thinking
Knowing
Question
-What theory did Dalton propose about the structure of matter?
-What did Rutherford discover about the structure of an atom?
-What did Bohr contribute to the modern atomic theory?
2
Comprehension/or
ganizing
3
Applying
-How is Dalton’s atomic theory alike and different from the modern
atomic theory?
-How did Ernest Rutherford discover the nucleus?
-What evidence did Thomson have that his glowing beam contained
negative particles?
-What evidence did Thomson provide about the structure of an atom?
In the Rutherford experiment, why weren’t all the alpha particles
deflected?
-Why must indirect evidence be used to study the structure of atoms?
-What evidence convinced Dalton that elements must be made of
individual particles called atoms?
-What is the main difference between Bohr’s model of the atom and
that atomic theory that is currently accepted?
Why was Dalton’s model of the atom changed after Thomson’s
experiment?
4
Analyzing
-Explain why scientists accepted Dalton’s atomic theory but not the
idea of an atom proposed by the Greek philosophers?
5
Generating
-If you observed a beam of particles being bent toward a negatively
charged plate, what might you conclude?
- How would the results of Thomson’s experiment change if the beam
were a stream of neutrons instead of a stream of electrons?
-Create a survey you could use to determine what people know about
the modern model of the atom. Figure out the best order for the
questions to test someone’s knowledge fairly. Be prepared to explain
your choices.
6
Integrating/
Synthesis
7
Evaluating
8
You Choose:
Comprehension or
Applying
9
You Choose:
Analyzing or
Generating
10
You Choose:
Integrating or
Evaluating
-Judge which atomic model is the most significant to our
current understanding of the atom? Please support your
answer.
-Was Rutherford’s model of an atom incorrect or incomplete?
Explain your answer.
Student Generated Quiz:
Atomic Structure & History
Create a 10 question quiz related to Atomic Structure & History. You must use a question stem from each level of
thinking on the Marzano chart provided for you. You must also attach an answer key to your quiz. You may just
see your questions on our next quiz or test!
No.
1
Level of Thinking
Knowing
2
Comprehension/or
ganizing
3
Applying
4
Analyzing
5
Generating
6
Integrating/
Synthesis
7
Evaluating
8
You Choose:
Comprehension or
Applying
9
You Choose:
Analyzing or
Generating
10
You Choose:
Integrating or
Evaluating
Question
History of the Atom
Democritus
400 BC
Aristotle
400 BC
John Dalton
1800’s
J. J. Thompson
1897
Major
Contribution
Major Contribution
Major Contribution
Transformed _____________
ideas on atoms into a
_______________________
Major Contribution
Discovered the ___________
Proposed the ____
______________
Other Information:
Stated that _____
substances are
made of 4
_________.
1.
2.
3.
4.
Other Information:
Conducted the ___________
______________ experiment
Dalton’s Atomic Theory
1) All _________ is made of
tiny ______________
particles called __________
2) The atoms of the same
element are ______________,
those of different elements are
______________
Major
Contribution
Determined the
____________and
______________
of the electron
Cathode Ray Tube Experiment
By adding an _________________
he found that the moving pieces
were _____________________
3) Atoms of different
____________ combine in
small, _____________ ratios
to form _________________
4) Chemical reactions involve
the ___________________ of
atoms. No new atoms are
________________________
(Law of _________________
_______________________)
Robert Millikan
1909
Use the diagram above to sketch the
results of Thomson’s experiment
Plum pudding model
Displays electrons
______________ in a
sphere of __________ charged
material
Use the diagram above
to sketch the model
Conducted ______
_______________
by measuring the
effect of an
electric field on
very small oil
droplets.
From the _______
of the drop and
the ________on
the plates, he
calculated the
____________on
an _____________
History of the Atom Continued
Ernest Rutherford
1912
Neils Bohr
1913
Major Contribution
Discovered the
___________________
Gold Foil Experiment
Expected Results
Gold Fold Experiment
Actual Results
Rutherford’s Model
Atoms
of gold
foil
Au foil
Au Foil
Screen
Use the diagram above to
sketch the EXPECTED
behavior of the alpha
particles
Screen
Use the diagram above to
sketch the ACTUAL
behavior of the alpha
particles
Major Contribution
Proposed that an ______is
found only in specific
circular paths, or _______,
around the _____________
Bohr’s Model
Referred to as __________
_______because electrons
move around the
____________ like planets
around the ________
Use the diagram of the
above to sketch the
behavior of the alpha
particles according to
Rutherford’s proposed
model
Major
Contribution
Confirmed the
existence of
__________in the
_______________
Modern View
Current
-The _________
is mostly
_________ space
-The atom
consists of
_______ regions
-Nucleus in
center and
contains ______
and __________
See Prentice Hall Text p. 107 or
Modern Chemistry pp.72-73
Rutherford made 2 major conclusions from his Gold Foil Experiment:


Sir James
Chadwick
1932
The ______________ is made up of mostly ______________________
The atom contains a ____________________________ piece at center
What experimental evidence led to Rutherford’s conclusion?
Use the diagram above to
draw a Bohr model of a
Lithium Atom
-The __________
_______ is the
region where
electrons in
areas of high
______________
called atomic
______________
History of the Atom
Democritus
400 BC
Aristotle
400 BC
Major
Contribution
Major Contribution
Stated that all
substances are
made of 4
elements.
Proposed the idea
of the atom
-Greek
philosopher
- smallest unit of
matter atomos
-competing ideas
with Aristotle
John Dalton
1800’s
Major Contribution
Transformed Democritus’
ideas on atoms into a
scientific theory
J.J. Thomson
1897
Major Contribution
Discovered the electron
Conducted the Cathode Ray
Tube experiment
Dalton’s Atomic Theory
1.
2.
3.
4.
earth
fire
water
air
-Greek Philosopher
-Ideas were carried
throughout the
middle ages
1) All matter is made of tiny
indivisible particles called
atoms
2) The atoms of the same
element are identical, those of
different elements are
different
3) Atoms of different
elements combine in small,
whole-number ratios to form
compounds
4) Chemical reactions involve
the rearrangement of atoms.
No new atoms are created or
destroyed (Law of
conservation of mass)
Robert Millikan
1909
Cathode Ray Tube Experiment
By adding an electric field he found
that the moving pieces were
negative
Use the diagram above to sketch the
results of Thomson’s experiment
Plum pudding model
Displays electrons
embedded in a sphere
of positively charged
material
Use the diagram above
to sketch the model
Major
Contribution
Determined the
mass and charge
of the electron
Conducted oil
drop experiment
by measuring the
effect of an
electric field on
very small oil
droplets.
From the mass of
the drop and the
charge on the
plates, he
calculated the
charge on an
electron
History of the Atom Continued
Lord Rutherford
1912
Neils Bohr
1913
Major Contribution
Discovered the nucleus
Gold Foil Experiment
Expected Results
Gold Fold Experiment
Actual Results
Rutherford’s Model
Bohr’s Model
Atoms
of gold
foil
Au foil
Au Foil
Screen
Screen
Use the diagram above to
sketch the expected
behavior of the alpha
particles
Use the diagram above to
sketch the actual behavior
of the alpha particles
Major Contribution
Proposed that an electron
is found only in specific
circular paths, or orbits,
around the nucleus
Referred to as Planetary
Model because electrons
move around the nucleus
like planets around the sun
Use the diagram of
the above to sketch
the behavior of the
alpha particles
according to
Rutherford’s
proposed model
Most alpha particles passed through the gold atoms (Only a few were greatly
deflected) leading to the conclusion that atom is mostly empty space
Therefore, the mass and positive charge are concentrated in a small region of the
atom, which he coined the nucleus. The particles that approach the nucleus are
deflected
Major
Contribution
Confirmed the
existence of
neutrons in the
nucleus
Modern View
Current
-The atom is
mostly empty
space
-The atom
consists of two
regions
See Prentice Hall Text p. 107
or Modern Chemistry pp.7273
Rutherford made 2 major conclusions from his Gold Foil Experiment:
 The atom is made up of mostly empty space
 The atom contains a small, dense, and positive piece at center
What experimental evidence led to Rutherford’s conclusion?
Sir James
Chadwick
1932
Use the diagram above to
draw a Bohr model of a
Lithium Atom
-Nucleus in
center and
contains protons
and neutrons
-The electron
cloud is the
region where
electrons in
areas of high
probability
called atomic
orbitals