Alchemy Unit
Investigation III:
A Particulate World
Lesson 1: Pudding and Clouds
Lesson 2: Building Atoms
Lesson 3: Subatomic Heavyweights
Lesson 4: Life on the Edge
Lesson 5: Shell Game
Lesson 6: Go Figure
Lesson 7: Technicolor Atoms
Alchemy Unit – Investigation III
Lesson 1:
Pudding and Clouds
ChemCatalyst
In the 5th century BCE a Greek
philosopher named Leucippus and his
student, Democritis, stated, “All matter is
made up of particles that can be divided
called atoms.”
• What do you think atoms are?
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
The Big Question
• How have chemists thought about the
atom through history?
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
You will be able to:
• Describe some models of an atom and
explain how they differ.
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Unit 1 • Investigation III
Notes
• Atoms are extremely small particles,
which cannot be seen, even with
microscopes.
• All matter is made up of atoms.
• Scientists have created models to
describe atoms. Models are similar to
theories, but often include a picture or
physical representation.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
• When a model is supported by
scientific evidence it is often
accepted by the scientific community.
• Scientific evidence is a collection of
observations that many people have
made. Everyone agrees on the same
collection of observations.
• As new evidence is gathered, models
are refined and changed.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Activity
Purpose: This lesson will introduce you
to various models for the atom that have
appeared over the past two hundred
years. The descriptions of five models of
the atom are on a separate handout.
(cont.)
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Unit 1 • Investigation III
(cont.)
Five Models of the Atom
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Unit 1 • Investigation III
Making Sense
• Examine the date of the atomic
evidence and then put the five models
in the correct order of their introduction
to the world of science.
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Unit 1 • Investigation III
Notes
• An atom is mostly empty space.
• The rest consists of a nucleus, which
is located in the very center of the
atom, and electrons, which are
located around the nucleus.
• The nucleus is very small (it would be
nothing more than a tiny speck in our
drawings, if we were to draw it to
scale).
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Notes (cont.)
• The nucleus is also very dense and
consists of two types of particles—
neutrons and protons.
• A neutron is a neutral particle with no
charge on it.
• A proton is a positively charged particle.
• Tightly bound together, neutrons and
protons make a positively charged
nucleus.
(cont.)
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Unit 1 • Investigation III
Notes (cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Check-In
Here is a Bohr model of a carbon atom.
• List two things this model tells you
about atoms.
• List something this model does not tell
you about atoms.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Wrap-Up
• All matter is made up of extremely
small particles called atoms. These
particles are too small to be seen even
with a microscope.
• Science is theoretical and dynamic.
Models and theories are continually
being revised, refined, or replaced with
new models and theories.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Alchemy Unit – Investigation III
Lesson 2:
Building Atoms
ChemCatalyst
A Bohr model of a helium atom and a
beryllium atom are given below.
Helium, He
Berylium, Be
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
• List three similarities and three
differences.
• How do you think a gold atom is
different from a copper atom?
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Unit 1 • Investigation III
The Big Question
• What does the periodic table tells us
about the structures of different
atoms?
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
You will be able to:
• Use the periodic table to identify the
properties of an elements atom.
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Unit 1 • Investigation III
Notes
• Atomic number is the number of
protons in the nucleus of an atom.
• Mass number is the mass of an
individual atom.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Activity
Purpose: This lesson will formally
introduce you to atomic structure.
Beryllium Atom
Fluorine Atom
Carbon Atom
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
element
chemical
symbol
atomic
number
# of
protons
# of
electrons
# of
neutrons
beryllium
5
fluorine
10
6
18
lead
126
19
tin
35.45
39
70
tungsten
184
29
gold
atomic
weight
12
chlorine
potassium
mass
number
183.85
36
118
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Making Sense
• If you know the atomic number of an
element, what other information can
you figure out about the atoms of that
element?
• If you know the atomic number of an
element, can you figure out how many
neutrons an atom of that element has?
Can you come up with a close guess?
Explain.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Notes
• Mass number is the number of
protons plus the number of neutrons.
• Atomic mass is the “weight” or mass
of a single atom.
• Atomic weight is the decimal number
on the periodic table.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Check-In
Use your periodic table to identify the
following elements:
a) Atomic number 18
b) Has three electrons
c) Atomic mass of 16.0
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Unit 1 • Investigation III
Wrap-Up
• Each successive element has one
more proton than the element
preceding it.
• The atomic number is equal to the
number of protons.
(cont.)
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Unit 1 • Investigation III
(cont.)
• The number of electrons is equal to the
number of protons (as long as the
atom is neutral).
• The mass number is equal to the
number of protons plus the number of
neutrons (most of the mass is found in
the nucleus).
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Alchemy Unit – Investigation III
Lesson 3:
Subatomic Heavyweights
ChemCatalyst
A chemist investigating a sample of
lithium found that some atoms have a
lower mass than other atoms. The
chemist determined that the structures of
the two types of atoms would be similar
to the two drawings below.
(cont.)
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Unit 1 • Investigation III
(cont.)
• What is different about the two atoms?
• What is the atomic number of each atom?
• What is the mass number of each atom?
• Do you think they are both lithium atoms?
Why or why not?
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
The Big Question
• How do isotopes of an atom account
for the atomic weight of an element?
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
You will be able to:
• Predict the isotopes of an element.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Notes
• Atoms of the same element that have
different numbers of neutrons are
called isotopes.
• Atomic mass units (amu) are
“invented” measurement units of the
atomic mass.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Activity
Purpose: In this lesson you will
investigate isotopes and how they affect
atomic weight.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
boron atom 1
# protons
2
3
4
5
6
7
8
9
10
# neutrons
# electrons
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
Element
Boron
Chemical
Symbol
Atomic
Number
Atomic
Weight
# of
neutrons
B
5 or 6
Chlorine
17
Lithium
Vanadium
# of
# of
protons electrons
6.94
V
23
Nitrogen
7
Magnesium
Argon
Ar
39.9
18. 20.
or 22
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Making Sense
• Explain why the atomic weights listed
in the periodic table are not usually
whole numbers.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Notes
• While the element iron is defined as
being made up of neutral atoms with
26 protons and 26 electrons, not every
iron atom has the same number of
neutrons.
• Atoms that have the same number of
protons but different numbers of
neutrons are called isotopes.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Notes (cont.)
• What we call the atomic weight on the
periodic table is actually the average
atomic mass of that element’s naturally
occurring isotopes.
• Isotopes have similar chemical
properties in that they combine with
other elements to form similar
compounds.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
• Atomic Weight is the weighted
average of the atomic masses of
different isotopes taking into account
their abundance.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Check-In
• Predict the isotopes of carbon, C.
Which isotope is more abundant? How
do you know?
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Wrap-Up
• Elements may have anywhere from 2
to 10 naturally occurring isotopes.
• The atomic weight of an element listed
on the periodic table is actually the
average mass of the naturally
occurring isotopes of that element.
• Isotopes have the same number of
protons and electrons, but different
(cont.)
numbers of neutrons.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
• Isotopes of a single element exhibit
similar properties in that they form
similar compounds.
• Isotopes are referred to by their mass
numbers.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Alchemy Unit – Investigation III
Lesson 4:
Life on the Edge
ChemCatalyst
The three atoms below have similar
reactivity and chemical behavior.
• Where are these elements located on
the periodic table?
• What do you think might be responsible
for their similar properties?
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
The Big Question
• What accounts for the similar
chemistry of elements in the same
group?
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
You will be able to:
• Give the number of valence electrons
for an element.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Activity
Purpose: The various physical and
chemical properties of the elements can
be traced to the electrons. By studying
electrons further we may be able to
unlock the key to creating substances
similar to gold. This lesson will reveal the
arrangement of electrons within atoms.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Making Sense
• Explain how you can determine the
arrangement of an element’s electrons,
from the element’s position on the
periodic table.
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Unit 1 • Investigation III
Notes
• Bohr proposed that electrons could be
found in different shells around the
nucleus.
• The letter “n” is referred to as the
quantum number.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
• The outermost shell of each drawing is
called the valence shell.
• The valence shell contains the
valence electrons.
• All other electrons are considered core
electrons.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Check-In
Provide the following information for
element number 34.
a) The element’s name and symbol.
b) The number of protons in the nucleus.
c) The total number of electrons for this
element.
d) The number of core electrons for this
element.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
e) The number of valence electrons.
f) The group number for this element.
g) The names of other elements with
similar chemistry.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Wrap-Up
• Electrons occupy different shells
around the nucleus of an atom.
• Each electron shell can hold a specific
maximum number of electrons.
• The valence electrons are in the
outermost electron shell of an atom.
Electrons that are not valence
electrons are called core electrons.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
• Elements with the same number of
valence electrons have similar
chemistry and are in the same group.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Alchemy Unit – Investigation III
Lesson 5:
Shell Game
ChemCatalyst
The two drawings show two ways of
representing the electron arrangement of
the element calcium, Ca.
• Name at least two differences.
• Name at least two similarities.
1
4
3
2
4pp
2pp
3d
2s
1s
4sp 3pp 3sp
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
The Big Question
• How do electron subshells relate to the
periodic table?
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
You will be able to:
• Identify an element based on its
electron configuration.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Notes
• Electron shells are divided into
electron subshells.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Activity
Purpose: This lesson introduces you to
electron subshells. You will explore how
they are related to the periodic table.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
4pp
2pp
3d
2s
1s
4sp 3pp 3sp
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
Electron configuration
1s22s1
1s22s22p3
1s22s22p63s23p5
Element
nitrogen, N
1s22s22p63s23p64s23d6
1s22s22p63s23p64s23d104p2
1s22s22p63s23p64s23d104p65s24d105p4
tellurium,Te
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Making Sense
• How is the organization and structure
of the periodic table related to electron
subshells?
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Notes
• An electron configuration is a list of
all the subshells that have electrons for
a given element. The number of
electrons in a subshell is specified as a
superscripted number.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Check-In
• Identify the element with the following
electron configuration.
1s22s22p63s23p64s23d104p3
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Wrap-Up
• Electron shells can be divided further
into subshells, referred to as; s, p, d, f.
• Each subshell can hold a specific
maximum number of electrons. The s
subshell can hold 2 electrons, the p
subshell can hold 6, the d subshell can
hold 10 electrons, and the f subshell
can hold 14.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
• The periodic table can assist us in
figuring out the sequence of filling the
subshells with electrons.
• Chemists keep track of electrons and
the subshells they are in by writing
electron configurations.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Alchemy Unit – Investigation III
Lesson 6:
Go Figure
ChemCatalyst
Consider the following electron
configuration:
1s22s22p63s23p64s23d104p4
• What element do you think is
represented by this electron
configuration?
• How many valence electrons do you
think this element has? Explain your
reasoning.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
The Big Question
• Where are the valence electrons in
electron configurations?
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
You will be able to:
• Write electron configurations and
name valence electrons for an
element.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Activity
Purpose: This activity teaches you a
shorthand way to keep track of electron
arrangements and how to identify
valence electrons.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
Element
Electron configuration
1s22s22p3
No. of
valence
electrons
Identity of
valence
electrons
2s22p3
5
1s22s22p63s23p1
1s22s22p63s23p64s23d2
4s23d2
2 or 4
1s22s22p4
Chlorine
1s22s22p63s23p64s23d104p65s1
Barium
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
Element
Electron configuration
No. of
valence
electrons
Identity of
valence
electrons
1s22s22p63s23p64s23d104p65s24d105p6
Silver
5s2
1 or 2
Potassium
Mercury
2
6s2
Terbium
2
6s2
2,3,4,5,6
4s23d4
Chromium
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
Element
Electron configuration
Valence electrons
Lithium, Li
[He] 2s1
2s1
Potassium, K
[Ar] 4s1
4s1
Scandium, Sc
[Ar] 4s23d1
4s2 3d1
Zinc, Zn
[Ar] 4s23d10
4s2
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Making Sense
• If you know the electron configuration
of an element, what other information
can you figure out? List at least six
things.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Check-In
• Write the electron configuration for
bromine, Br.
• Write the noble gas electron
configuration for Br.
• How many valence electrons does Br
have? Explain.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Wrap-Up
• The noble gases can be used as
placeholders in the periodic table when
writing electron configurations.
• In the d-block or transition elements
we find some exceptions to the rules
when determining valence electrons.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Alchemy Unit – Investigation III
Lesson 7:
Technicolor Atoms
ChemCatalyst
The ancient alchemists heated atoms to try
to change them into gold. Knowledge of
atomic structure assists us in figuring out
what parts of an atom can be changed.
• Let’s say we started with a lithium atom
and changed different parts of the atom.
Look at the lithium atom below and four
possible changes to it. What would we
end up with in each case?
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
The Big Question
• What part of the atom is changed by
heating?
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
You will be able to:
• Predict the color of the flame produced
when heating a substance.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Activity
Purpose: In this activity you will observe
evidence that atomic structure is
changed when atoms are heated.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
Safety Note:
• Tie back long hair.
• Keep long sleeves and clothing away
from the flames.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
Note: Do not exchange wires. For each
solution, only use the wire that is already
in that solution. After you use the wire,
be sure to put it back in the solution from
which it came.
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Substance Name
Color of Flame
sodium carbonate
potassium nitrate
copper nitrate
strontium nitrate
potassium chloride
sodium chloride
copper sulfate
strontium chloride
sodium nitrate
potassium sulfate
copper wire
copper penny
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Making Sense
• The yellow color of the flame for sodium
indicates that the sodium atoms changed
in some way when they were heated.
Consider the following possibility that the
electron configuration of sodium changed
from [Ne]3s1 to [Ne]4p1. What is the
difference between [Ne]3s1 and [Ne]4p1?
(Are the total number of electrons the
same? Are the electrons in the same
locations?)
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
(cont.)
• Do you think gold can be made by
changing the arrangement of electrons
in atoms? Explain.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Notes
Red
Blue/Green
strontium nitrate
strontium chloride
copper nitrate
copper sulfate
copper solid
copper penny
Yellow/Orange
Pink/Lilac
sodium carbonate
sodium chloride
sodium nitrate
potassium nitrate
potassium chloride
potassium sulfate
(cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Notes (cont.)
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Check-In
• Predict the colors of the flames
produced when heating the following
substances. Explain your thinking.
Copper carbonate
Magnesium sulfate
© 2004 Key Curriculum Press.
Unit 1 • Investigation III
Wrap-Up
• Electrons can move between subshells
within an atom.
• An energy exchange occurs when
electrons move farther away from the
nucleus, or when they return to their
original subshell.
• Moving electrons within an atom does
not change the identity of the atom.
© 2004 Key Curriculum Press.
Unit 1 • Investigation III