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Copy and complete the following:
◦ Locate the Halogens and Noble Gases on the
Periodic Table.
 To what Group are they each located?
Physical Science
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When two or more atoms attach to each
other, they form a chemical bond
Compounds are any two elements
chemically bonded
◦
◦
◦
◦
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Water
Sugar
Salt
And almost all other substances!!!!
Electrons are responsible for the type,
strength, and size of a chemical bond
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Bohr-Rutherford diagrams are large and
difficult to show relationships between
multiple atoms
Lewis diagrams are used to show multiple
atoms
Lewis diagrams show only the valence
electrons
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Valence electrons form the charge of an atom
Electrons are always trying to get together in
groups of 8 (forget shells for a minute)
Elements that have 8 valence electrons have
FULL outer groups
We call these elements NOBLE or INERT gases,
they are found in group 8
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Label the Nobel (Inert) gases on your chart
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Elements with 1 valence electron are called
the Alkali metals (group 1) (Label)
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Elements with 2 valence electrons are called
the Alkaline Earth metals (group 2) (Label)
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Elements with 7 valence electrons are called
the Halogens (group 7) (Label)
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Consist of
◦ Element Symbol
◦ Electrons in each open spot
Sy
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7
Draw the element symbol
Determine the # valence electrons
Starting at the top, going clockwise, place
one electron in each spot around the
element symbol
Cl
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Draw the Lewis Structure for Aluminum!
Al
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Draw the Lewis Structure for Lithium!
Draw the Rutherford-Bohr Diagram for
Lithium!
-
Li
3P
3N
-
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Writing a charge
◦ Valence electrons, Bohr-Rutherford, and Lewis
diagrams are used to determine charge
◦ Charges are a shortcut to determining bonding
properties
◦ RULES OF CHARGE
 IF the # of valence electrons is GREATER than 4, the
charge is negative (Mostly)
 IF the # of valence electrons is less than 4, the charge is
positive (Mostly)
 Charges are in reference to a full shell of 8
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For example, Aluminum has 3 valance
electrons
◦ The possible charges are +3 OR -5
◦ It either has 3 OVER a full shell, or 5 LESS than a full
shell
◦ Because the number 3 is less than 4, we use the
charge of +3
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Any element with a
charge is called an
ION, the charge is
an ionic charge
What are the ionic
charges of the
elements in the
table?
Sodium?
+1
Nitrogen? -3
Oxygen?
-2
Argon?
0
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A few exceptions!
◦ Metals are always a positive charge!!
◦ Non metals are always negative!!
◦ Metalloids can go either way (you are not
responsible for choosing – I will tell you)
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Example: Boron
◦ According to rule of 4’s….its a +3 charge
◦ But since it’s a nonmetal, we use -5!
1.
2.
3.
4.
All compounds must have neutral charges
(That means the positive charges (cations)
and the negative charges (anions) must
equal
Subscript numbers are used to show the
number of ions
Coefficients are used to show the number of
molecules
2H2O
Coefficient
Subscript
1 atom of O
“1’s” are
implied and
not written
Subscript
2 atoms of H
H2O
H
H
O
H2O
O
H
H
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Try this one!
NaCl (table salt)
Na Cl
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Last One!
Aluminum Bromide
Br Al Br
Br
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Several Types including
◦ Covalent Bonds*
◦ Ionic Bonds*
◦ Metallic (only between metals)
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Electrons are shared between two or more
atoms
Covalent bonds can exist between atoms of
the same type…for example N-N (N2) or OO (O2)
Covalent bonds can form single, double, or
triple bonds
Covalent bonds are strong and usually
result in stable molecules
Carbon always forms covalent bonds and
forms the basic molecules for all life
substances
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Usually formed by members of the Alkali
group (ones with +1 electron)
Electrons are donated to another molecule
Between elements from opposite sides of the
chart
Forms crystals (salts) & most dissolve in water
1.
2.
3.
4.
Write ions with charges
Cross charges
Write subscripts (omit “1’s”)
Use parenthesis if needed

What is the molecular formula of water?
+1
H
H2
-2
O
O1
H2O
O
H
H
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What is the molecular formula of carbon
dioxide?
+4
C
C2
-2
O
O4
C2O4
CO2
Yikes!
Reduce like a fraction to
lowest denominator
****note****
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What is the molecular formula of a compound
that has aluminum and sulphur?
+3
Al
-2
S
Al2 S3
Al2S3
Any guesses
on the
name?
Binary Covalent
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Ionic - Starts with a metal
◦ Swaps valence electrons
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Covalent - 2 non metals
◦ Shares valence electrons
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Before you can name binary covalent
compounds, you MUST know the prefixes!
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Mono
Di
Tri
Tetra
Penta
Hexa
Hepta
Octa
Nona
Deca
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1
2
3
4
5
6
7
8
9
10
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Name the prefix for the number of atoms of
the first element
Then name the first element
Name the prefix for the number of atoms of
the second element
Than name the root of the second element
with the ending -ide
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No charges are used in Binary Covalent
Compounds
If the 1st prefix is mono….DROP IT!
When the prefix ends in an o or a, and the
name of the element begins with a vowel, the
o or a is often dropped
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What is the name of N2O4?
◦
◦
◦
◦
◦
N2  di
nitrogen
O4  tetra
oxide
Since oxide begins with a vowel, we will
drop the a in tetra
Dinitrogen tetroxide
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Name SO2
◦ S  mono sulfur
◦ But mono is with the 1st element, so it will be
dropped  sulfur
◦ O2  dioxide
◦ Sulfur dioxide
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Write the formula for dichlorine monoxide
◦ Dichlorine  Cl2
◦ Monoxide  O
◦ Cl2O
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Write the formula for disulfur dichloride
◦ Disulfur  S2
◦ Dichloride  Cl2
◦ S2Cl2
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Before we can name compounds, we must
know the rules for writing formulas
The modern model of how atoms react to
form compounds is based on the fact that
the stability of a noble gas results from the
arrangement of its valence electrons.
This model of chemical stability is called the
octet rule.
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Elements will gain or loose electrons to
have 8 valence electrons.
To review, how many valence electrons does
Na have?
1
What will happen to that valence electron
You will loose that electron
If you loose that electron, what charge will
you have?
+1
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Group
Group
Group
Group
4
Group
Group
Group
Group
1A
2A
3A
4A




+1
+2
+3
+4 / -
5A
6A
7A
8A




-3
-2
-1
STABLE
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The charges of
monatomic ions, or
ions containing only
one atom, can often
be determined by
referring to the
periodic table
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An ion is an atom or group of combined atoms that
has a charge because of the loss or gain of
electrons.
A compound that is composed of ions is called an
ionic compound.
Only the arrangement of electrons has changed.
Nothing about the atom’s nucleus has changed.
Ionic compounds are usually start with a metal or a
polyatomic ion (like ammonium)
In ionic compounds, you will SWAP valence
electrons
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A cation, or positive ion, is formed when an
atom loses one or more electrons.
An anion, or negative ion, is formed when an
atom gains one or more electrons.
A monatomic ion is one element with a
charge
A polyatomic ion is more that one element
with a charge
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Remember that objects with opposite charges
attract each other.
The strong attractive force between ions of
opposite charge is called an ionic bond.
Don’t forget that even though the ions have
charges, the overall charge of the compound
will be …
ZERO!
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Write the formula for the compound formed
between sodium and chloride
Na  Na +1
Cl  Cl -1
Na+1 Cl-1 (criss-cross charges & reduce)
Na1Cl1
(What’s wrong here?)
Do Not write the 1’s
NaCl
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Write the formula between Mg and Br
Mg  +2
Br  -1
Mg+2 Br -1 (Bring down charges)
MgBr2
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Write the formula for the compound formed
between Ca and S
Ca  Ca +2
S  S -2
Ca+2 S-2 (Bring down charges)
Ca2S2
(What’s wrong?)
Simplify!
CaS
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Copper (II) and chlorine
Silver and nitrogen
Magnesium and sulfur
Calcium and selenium
Potassium and oxygen
Lithium and phosphate
sodium and chlorine
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CuCl2
Ag3N
MgS
CaSe
K2O
Li3PO4
NaCl
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You have to remember the elements that
form multiple charges (the ones with the
roman numerals)
That roman numeral will tell you the charge!
For example: Copper (II)  Cu +2
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Copper
Iron
Lead
Tin
Gold
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+1
+2
+2
+2
+1
and
and
and
and
and
+2
+3
+4
+4
+3
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In naming ionic compounds, name the cation
first, then the anion.
Monatomic cations use the element name.
Monatomic anions use the root of the
element name plus the suffix -ide.
(This means 1 element with a negative charge
will end in –ide).
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If an element can have more than one
oxidation number, use a Roman numeral in
parentheses after the element name, for
example, iron(II) to indicate the Fe 2+ ion.
For polyatomic ions, use the name of the ion.
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All you have to do is name the 1st thing then
name the 2nd thing
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NaCl
MgS
K3 P
CaCl2
CuBr
AlCl3
CuS
Fe3N2
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Sodium chloride
Magnesium sulfide
Potassium phosphide
Calcium chloride
Copper (I) bromide
Aluminum chloride
Copper (II) sulfide
Iron (II) nitride
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Lead (IV) Oxide
Potassium fluoride
Iron (II) chloride
Calcium sulfide
Lithium nitrode
Sodium selenide
Tin (II) chloride
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PbO2
KF
FeCl2
CaS
Li3N
Na2Se
SnCl2
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KCl
CO2
Na2S
LiBr
CuI2
Fe2O3
Al2O3
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Potassium chloride
Carbon dioxide
Sodium sulfide
Lithium bromide
Copper (II) iodide
Iron (III) oxide
Aluminum oxide
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Carbon tetrachloride
Phosphorous pentachloride
Aluminum oxide
Copper (II) nitrate
Chlorous acid
Hydrophosphoric acid
Iron (III) hydroxide
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CCl4
PCl5
Al2O3
Cu(NO3)2
HClO2
H3P
Fe(OH)3