M9
THE ATOM
Foundational Research Package
III
AN “EVEN CLOSER” LOOK AT THE STRUCTURE OF MATTER:
AN INTRO TO STRUCTURAL FORMULAS AND BONDING
January 2008 - Team E Science
Name: ____________________________________
Section: ______________________________
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TABLE OF CONTENTS
Study Guide……………………………………………………….…3
Review and Introduction…....…………………………………4
Overview: How to Make Water
A Look at the Making of a Molecule……………………5-6
Notes
How do scientists predict, illustrate, and show the
chemical reaction that occurs
when atoms bond? ……………………………………….......… 7-9
How do atoms “get together” (i.e. bond)?...............10-12
Practice
Chemical equations and structural formulas………….13
Bonding Rules……………………………………………………….14
Synthesis Activity………………………………………………....15
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AN “EVEN CLOSER” LOOK AT THE STRUCTURE OF MATTER
How do scientists predict, illustrate, and show chemical bonding? How do atoms “get together” (i.e. bond)?
An Intro to Structural Formulas and Bonding
STUDY GUIDE
For the quiz on ________________________ you need to know…
1. two reasons why atoms must bond with one another.
2. which part of the atom is involved in bonding.
3. what the three types of bonds are and what happens to the atoms that undergo each of those
bonds.
4. which subatomic particle is involved in the bonding process.
5. what type of reaction occurs when atoms bond.
6. what an ion is and how it is formed.
7. how to write and balance a simple chemical equation.
8. what the “reactants” and “products” are in a chemical equation.
9. what the meaning and purpose of “coefficients” and “subscripts” are in a chemical equation.
10. how to create a Lewis Structure/Electron Dot Diagram.
11. how to create a structural formula.
12. what it means for an atom to be “stable” and/or “happy.”
13. what it means for an atom to be “amphoteric.”
14. what it means for an element to be “diatomic.”
15. what atoms need in order to make a bond happen and the force that keeps atoms bonded.
16. how to determine the number of valence electrons and the valence number of an atom.
17. which families of elements in the periodic chart are “stable/happy,” “losers,” and “gainers.”
18. how to predict what type of bond atoms will make with one another.
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AN “EVEN CLOSER” LOOK AT THE STRUCTURE OF MATTER
How do scientists predict, illustrate, and show chemical bonding? How do atoms “get together” (i.e. bond)?
An Intro to Structural Formulas and Bonding
REVIEW:
Do you remember where bonding occurs in an atom? Do you remember why bonding must occur between
atoms? Do you remember the three ways that atoms can “get together” (i.e. bond!)? If you remember
SOMETHING from Friday’s quickie intro lecture on bonding OR any of the lectures before break…write it in the
space below…even if it is only one idea or word or concept! Just get those brain cell juices flowing and try to remember
what we’ve discussed so far about BONDING…it will help you get ready for our Intro to CHEMICAL
EQUATIONS, STRUCTURAL FORMULAS, and BONDING discussion!
1) Why must bonding occur between atoms? ____________________________________________________
2) Where does bonding occur in an atom? ______________________________________________________
3) What are the three ways that atoms can bond? _________________________________________________
INTRODUCTION: The overview of the “Why, Where, and What” of bonding
It is important that atoms bond. Why? Because they need to bond in order to make _____________,
_______________, and other more complex forms of matter. For example, if atoms didn’t bond, you would be
quite thirsty all the time! Yes, ______________ is the result of the process of CHEMICAL bonding. To make
this compound, ___________ and ______________ must be _______________ bonded (not only physically
bonded) together. WARNING: when this is done, you can make quite an explosion, believe it or not!
Bonding occurs between the _______________ shells of atoms. It is here that electrons are
__________, ______________, or ________________. When atoms ____________, ___________, or
_________ electrons, they are no longer neutral and are now called _________. The ______ are attracted to one
another due to the ________________ force and a bond forms to make a _________________ . Keep in mind
that bonding is the result of a _______________ reaction – NOT ONLY physical mixing of the atoms!
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OVERVIEW: How do you make water?
A Look at the Making of a Molecule
Recipe for H20 (Yield: 2 molecules)
Step 1. Gather your base ingredients (elements/atoms) by looking at the MOLECULAR FORMULA.
Step 2. Find the number of valence electrons and valence # of each of your ingredients (elements/atoms).
Element/Atom
Column # on Periodic
Table
# of Valence e-
Valence #
Step 3. Predict using ELECTRON DOT DIAGRAMS (Lewis Structures).
Step 4. Analyze what each ingredient (element/atom) needs to be “happy.”
Step 5. Gather all necessary ingredients (elements/atoms)!
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Step 6. Bond your ingredients (elements/atoms) using the ELECTRON DOT DIAGRAMS; fill in the missing
spaces to create “happiness” for all ingredients.
Step 7. Turn your bonded Electron dot diagrams into STRUCTURAL FORMULAS.
Step 8. Analyze the TYPE OF BOND made.
Step 9. Write out the CHEMICAL EQUATION. Be aware of DIATOMIC ELEMENTS! (H2 I2 Br2O2 N2 Cl2 F2)
Step 10. Use COEFFICIENTS to balance your equation.
Step 11. Wait for the “BOOM” and then enjoy your tasty treat. Yield: 2 molecules of H20
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PART I: How do scientists predict, illustrate, and show the chemical reaction that
occurs when atoms bond?
 Scientists may use ____________ MODELS or _______________ DOT DIAGRAMS (a.k.a. LEWIS
STRUCTURES) to predict bonding between atoms.
 Scientist show how atoms bond by writing ___________ __________ and __________ ___________.
 For chemical equations:

Molecular formulas consisting of the correct combination and number of atoms are used to represent the
molecules and/or atoms that are being bonded. (e.g. H2O is the molecular formula for water!)
An “
” is used to show what substance(s) is/are being “yielded” or chemically produced.
Atoms on the LEFT side of the arrow are referred to as REACTANTS and the atoms on the RIGHT side
of the arrow are referred to as PRODUCTS.
And, most importantly, the equation is BALANCED…just like in algebraic math! To do this, a number is
placed before the molecular formulas to balance the amount of atoms on each side of the equation --- this
number is called a COEFFICIENT. FYI…the number below and to the right of each chemical symbol is
called a SUBSCRIPT.
2H2O



Coefficient
Subscript
Chemical equation examples:
H20 (water)
1)
CH4 (methane)
2)
 For structural formulas:





An electron dot diagram or Lewis structure is created for atoms involved in the chemical bonding process.
A chemical symbol is used to represent the atoms that are being bonded.
The appropriate number of dots is drawn on the four sides of the chemical symbol to represent the
number of valence electrons and “empty spots” in the valence shell of the bonding atoms.
Structural formulas are used to represent what the atoms look like when they are “brought together” in the
chemical bond. To show this, the electron dot diagrams for each atom are drawn and puzzle-pieced
together by filling their “empty spots” with each other’s valence electrons. Hint: you might want to use
different symbols instead of dots for the electrons in each of the different atoms of the bonding molecule!
In the final structural formula, ALL dots are removed from the electron dot diagram and “bonded”
electrons are replaced with lines.
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
Because the Periodic Table is set up in a periodic, predictable way, we can predict what the Electron Dot
diagrams (a.k.a. Lewis Structures) look like for each of the 8 major columns of the Periodic Table.
Column
1
2
3
4
5
6
7
8
Number of
Valence
Electrons
Valence Number
Example
Element
Family
Lewis Structure
(Electron Dot
Diagram)
IMPORTANT:
 Imagine a box around the element symbol.
X
 Place the FIRST DOT on the right side and next to the first dot.
X
 Place the SECOND DOT next to the first dot.
X
 Place the remaining dots in a counterclockwise fashion…putting a maximum of two dots on each side of the
imaginary box around the element
X
X
X
X
X
 Keep in mind that the dots will not stay exactly in these positions when they bond with the atoms needs to
bond with other atoms!
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Here are the structural formulas of some common compounds and molecules:
Molecule Name
Molecular
Formula
Carbon dioxide
CO2
Ammonia
Vinegar
Sucrose
Structural Formula
O—C—O
H–N–H
NH3
H
CH3COOH
C12H22O11
(table sugar)
(YIKES!)
Electron Dot Diagram and Structural Formula Examples:
Molecular Electron Dot Diagram for First Atom
Formula
Electron Dot Diagram for Second Atom
Structural Formula
H20
(water)
CH4
(methane)
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PART II: How do atoms “get together” (i.e. bond)?
THE 7 SIMPLE RULES OF BONDING:
RULE #1 – All atoms want to be “happy.” “HAPPY” means that their ____________ ________ is
filled to the ___________ capacity ( ___ electrons for the first level and ___ electrons for all other levels).
ONLY the ___________ or ___________ gases are “happy” because they already have the ___________
amount of electrons in their _________________ shell.
HAPPY
NOT HAPPY
RULE #2 – To be “happy,” atoms will bond with one another. They will either __________,
_______________, or _________________ their _____________ e-!
RULE #3 Atoms will bond with each other ONLY if they can both be “_________” (i.e. have
____________ valence shells) when they “get together” or bond ___________________!
HAPPY
NOT HAPPY
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RULE #4 -
Atoms will do what is “easiest” --- that is, they will bond in a way that requires
them to use the LEAST amount of energy.
MAKING BONDS REQUIRES ENERGY! Atoms with a
valence that is LESS than ____________ will ___________ their electrons. Atoms with a valence that is
MORE than ____________ will ___________ electrons from another atom. Remember: it is BEST to
“GAIN if you have _________ e- and LOSE if you have _________ e- !” eg. Na – Valence e- = _____ 
_____________________
RULE # 5 – Elements that have exactly _____ electrons in their _______________ shell will EITHER
______ OR _________ electrons.
These elements are located in column _______! These elements are called
(ha-choo…extra credit…ah-hem) _________________________. This means that they can “go both ways” --- i.e.
________ or _________ electrons depending upon what the OTHER atom they are bonding with wants to do!
RULE #6 – By drawing the _______ model or SIMPLY looking at the ________________ #’s on the
periodic chart, you can figure out the number of ____________ electrons that an atom has and, thus, what it
needs to do to be “_________.”
Remember Mendeleev and his periodic pattern of VALENCE NUMBERS? The
top of the major columns can be labeled to reflect the number of electrons in the valence shell or the number of
electrons the atoms will _________ or ______________ to become happy! Label the diagram below!
The Periodic Table of the Elements
Less than four = ___________
More than four = __________
(# of valence e-)
___ ___
___ ___ ___ ___ ___ ___
(valence #)
___ ___
___ ___ ___ ___ ___ ___
_______ or _______
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RULE #7 – The families of the periodic chart have a tendency to be “losers” or “gainers”. Most
___________, because most of them have less than four electrons want to be ____________. Most
____________, because they have more than four valence electrons want to be _________________. Noble or
inert gases do ___________ want to __________ or ___________ ANY electrons…they are already happy
(i.e. ____________!).
THE TYPES OF BONDS:
BOND TYPE
and NICKNAME
DESCRIPTION
BONDING FAMILIES
EXAMPLE
One atom _________ electrons and
IONIC
give a little, take a little
COVALENT
sharin’ to make a pairin’
the other ________ electrons.
Atoms __________ their electrons.
The electrons of the atoms
METALLIC
lost at sea
“________” in a “sea” around the
positive nuclei of the atoms.
See here for examples of three bond types: http://www.chemcool.com/regents/chemicalbonding/aim5.htm
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PART I. CHEMICAL EQUATIONS AND STRUCTURAL FORMULAS
A. Fill in the missing information in the following chemical equations. You may need to fill in a symbol and/or
a coefficient to make each equation correctly written and balanced.
1. When heated, aluminum reacts with solid copper oxide to produce copper metal and
aluminum oxide.
Products
Reactants
2Al + ____CuO ____________
Al2O3 + ____Cu
2. Potassium Oxide is not a stable compound and, in the presence of water, it changes
into potassium hydroxide.
Products
Reactants
K2O + H2O
____KOH
Here are some more practice problems…
3.
Products
Reactants
2NaCl + BeF2
__NaF + BeCl2
4.
__AgNO3 + __LiOH
__AgOH + __LiNO3
5.
CH4 + ___O2
CO2 + 2H2O
6.
__Mg + __Mn2O3
__MgO + __Mn
B. Draw the electron dot diagrams (a.k.a. Lewis Structures) for the following atoms.
1.
F
2.
Ne
3.
B
4.
Mg
C. In the boxes draw the structural formulas for the following molecules by rewriting the electron dot diagrams
given.
1.
H Cl
2.
Mg O
3.
F
Be
F
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PART II. BONDING RULES
Match the term with the definition.
DEFINITIONS
TERMS
a) Metals
____ 1. The element family that usually LOSES
electrons.
b) non-metals
____ 2. The bond that occurs between non-metals.
c) inert gases
____ 3. The bond that occurs when one atom loses
electrons and the other gains electrons.
d) ionic bond
____ 4. The element family that usually GAINS
electrons.
e) metallic bond
____ 5. The element family that usually does NOT
bond easily with other elements.
f) covalent bond
____ 6. The group of elements that can either lose
or gain electrons.
g) amphoteric
____ 7. The bond that occurs between metals.
____ 8. The bond in which electrons “float” around
the positive nuclei of the bonding atoms.
____ 9. The bond in which atoms share their
valence electrons.
____ 10. The bond that occurs between non-metals
and metals.
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PART III. PUTTING IT ALL TOGETHER…Chemical equations, Structural Formulas, and Bonding Rules
Use your new bonding knowledge to figure out what types of bonds the following atom pairs would most likely
make! Fill in the family names, the # of electrons in their valence shell, their valence number (i.e. how many e- they want
to lose, gain, or share to be “happy”), the resulting bond name, and structural formula. Then write the BALANCED
chemical equation for the chemical reaction between the two atoms. DO NOT FORGET TO USE YOUR
PERIODIC CHART!
EXAMPLE 1.
ATOM
Family
NAME
Na
(Sodium)
Cl
(Chlorine)
# of
valence e-
Valence #
Electron Dot
Diagram
RESULTING
BOND
STRUCTURAL
FORMULA
Chemical Equation: ______________________________________________
EXAMPLE 2.
ATOM
Family
NAME
Al
(Aluminum)
Al
(Aluminum)
# of
valence e-
Valence #
Electron Dot
Diagram
RESULTING
BOND
STRUCTURAL
FORMULA
Chemical Equation: _____________________________________________
EXAMPLE 3.
ATOM
Family
NAME
C (Carbon)
# of
valence e-
Valence #
Electron Dot
Diagram
RESULTING
BOND
STRUCTURAL
FORMULA
O (Oxygen)
Chemical Equation: _____________________________________________
EXAMPLE 4.
ATOM
Family
NAME
K
(Potassium)
Br
(Bromine)
# of
valence e-
Valence #
Electron Dot
Diagram
RESULTING
BOND
STRUCTURAL
FORMULA
Chemical Equation: _____________________________________________
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