NOTE:
This presentation was not made for public
use. Please do not use this presentations
without my permission and the permission of
each of the authors of the photographs,
quotes, and other materials that they contain.
Thank you,
Vicki Hughes
Labs and Activities that go with this presentation:
Glowstick Bracelets
Marble, Cup, Spoon Catalyst
Oozing Pumpkins
CHEMICAL BONDING AND IONS
BONDS…Chemical Bonds…
…and Reactions
Antoine Lavoisier: Law of Conservation of Matter
“Matter is not gained or lost in chemical reactions.”
Discovered the role
oxygen plays in the
combustion of matter.
Annoying girlfriend
Lavoisier
O2
CO2
Chemical Formulas
Na
Sodium
Sodium Chloride
Cl
Chlorine
Chemical formulas tell you what
elements are in a compound…
H
Hydrogen
2
1
Dihydrogen
Hydrogen Oxide
Oxide
O
Oxygen
…and the number atoms
of each element.
Sometimes element names are
mixed into one name.
CH4 = methane
OH = hydroxide
Sometimes compounds have a
special non-elemental name.
Sometimes compounds have a
chemical name and a familiar
name.
H20 = Dihydrogen oxide = water
Familiar Name
Chemical Name
Chemical Formula
Sand
SiO2
Milk of Magnesia
Silicon Dioxide
Magnesium
Hydroxide
Mg(OH)2
Cane sugar
Sucrose
C12H22O11
Lime
Calcium Oxide
CaO
Vinegar
Acetic Acid
CH3COOH
Laughing Gas
Dinitrogen Oxide
N2O
Table Salt
Sodium Chloride
NaCl
When an element has a visible
number following it to indicate
more than one atom, the
number is written in lower case
and placed lower than the text
line. This number is called a
subscript.
CH4
subscript
Atoms are unstable if they have valence electrons that are unpaired.
Remember, valence electrons are those that are in the outermost shell.
To reach stability, atoms will bond with each other
so all of the valence electrons are paired.
Not paired
Not paired
Types of Chemical Bonds
Remember, a Chemical Bond is the force that occurs when two or
more atoms hold together.
When one atom gives up an e- to another atom, ions are formed.
The positive and negative charges caused by moving e-’s from one
atom to another causes an attraction between the ions.
The attraction bonds the atoms together in an IONIC BOND.
Remember Lewis structures?
Use Lewis structures to show bonding!
+
Na
Describe what you just saw.
Cl
Sometimes atoms share electrons instead of gaining and losing them.
This type of bond is called a COVALENT BOND.
H O
H
Covalent sharing is not always equal. In water, the e-’s spend most
of their time around the oxygen.
A covalent bond in which the e-’s spend more time with one atom
than the others is considered to be POLAR.
Water is an example of a polar
molecule. This unequal sharing
creates a slight negative charge
to one side of the molecule.
The polarity of water makes it a very good solvent (can dissolve many
other substances) because it can bond with lots of other atoms.
Why does salt dissolve in water so easily?
Multiple Bonds
Triple bond
N
N
When e-’s shift so that more than one pair is shared between two
atoms, multiple bonds are formed.
Remember, bonds are typically indicated with a line.
Sometimes those lines are connected to form shapes.
Chemical Bonding Animated Tutorials
http://www.kentchemistry.com/links/bonding/bondingflashes/bond_types.swf
Let’s Practice Making Bonds
http://www.learner.org/interactives/periodic/groups_interactive.html
Dot to Dot Puzzles
HCl
H2O
CO2 (double bonds)
CBr4
SO2
Li2S
Bonus:
N2O
Step 1: Do Lewis structures.
Na
Cl
Step 2: Put them together.
Cl
Dot to Dot Puzzles
HCl
H2O
CO2 (double bonds)
CBr4
SO2
Li2S
Bonus:
N2O
Let’s Check It!
http://www.drkstreet.com/r
esources/metallic-bondinganimation.swf
Metallic bonds involve a group of packed protons with a net of
electrons covering them.
Writing Formulas and Naming Compounds
The charge on an ion is called its oxidation number.
+
Na
Cl
A binary compound is made of two elements. (Bi=2)
NaCl
Writing Formulas and Naming Compounds
Metals always lose electrons. Nonmetals always gain electrons.
NONMETALS
METALOIDS
METALS
Gain e-’s become more negative
Lose e-’s become more positive
Oxidation numbers are the number of e-’s an element can
gain (and become -) or lose (and become +).
+1
+2
Oxidation numbers
can be added to the
periodic table….
METALS
NONMETALS
METALOIDS
+3
+4
-3
-2
-1
Writing Formulas and Naming Compounds
Special elements with more than one possible oxidation number.
NAME
OXIDATION NUMBER
Copper (I)
Copper (II)
1+
2+
Iron (II)
Iron (III)
Chromium (II)
Chromium (III)
2+
3+
2+
3+
Lead (II)
Lead (IV)
2+
4+
Writing Formulas and Naming Compounds
Ions alone have oxidation numbers…
+
Na
Cl
But when they combine, their compounds are neutral.
NaCl
Writing Formulas and Naming Compounds
The oxidation numbers of the combining positive and
negative ions must balance with each other.
+
Na
Cl
So that when they combine, their compounds cancel each
other out.
NaCl
Writing Formulas and Naming Compounds
You can name a binary ionic compound
from the formula using these rules:
ACT L8, L9 & L10
1. Write the name of the positive ion.
2. Check to see if the positive ion can have more than one
oxidation number (see the previous table). If it has more than one,
look at your formula and write the charge of the positive ion in
roman numerals inside parentheses. Ex: Iron (II)
3. Write the root name of the negative ion. Ex: chlorine = chlor
4. Add the ending –ide to the root.
Name this compound.
2+
Fe
_
+ 2F  Fe(II)F2
Iron (II) Flor ide
CHEMICAL REACTIONS
Chemical Equations
Scientists write out the reactions of combining chemicals as
chemical equations using symbols from the periodic table.

+
+
Na
+
Cl
 NaCl
Chemical Equations
Remember…
The elements that are reacting with each other are called the
reactants and are shown on the left side of the action arrow.
+
Na
+
Cl
Reactants
 NaCl
Products
The compounds formed by the reaction are called products and
are shown on the right side of the action arrow.
Reduction-Oxidation Chemical Reactions
Oxidation refers to a chemical
reaction that commonly involves
oxygen.
Oxidation is a reaction in which
an atom loses electrons.
The atom that loses electrons is
said to be oxidized.
Examples: rusting of iron,
burning of paper. Heat is usually
given off.
Which element
is oxidized?
Fe2O3
Reduction-Oxidation Chemical Reactions
Reduction is the opposite
of oxidation.
Reduction involves the
gaining of electrons and
the element is negative.
The element that gains e-’s
is reduced.
A reduced material takes
electrons and heat is
absorbed.
Which element
is reduced?
Fe2O3
OIL RIG
What this stands for is:
Oxidation Is Loss of electrons
Reduction Is Gain of electrons
Redox is the shortened term
used to identify a reductionoxidation reaction.
Once upon a time…
A wicked witch called Chemis cast a spell on all of Equazious
turning the people into Trynots. The spell remained powerful as
long as the people in the village of Ractant didn’t discover how
to balance their wealth with the people of Produk, which was
across the Arrow River.
One day a young man named Steudint of the town of Balancia in
the nearby mountains learned about a powerful potion. It was
said this potion could balance the wealth of the two peoples and
would create great harmony in the land forever.
So Steudint searched the mountains for the ingredients in the
potion and raced to the land of Equazious. However, because
Chemis had learned of his plan, Steudint had to distribute the
ingredients among the peoples to keep until the witch as not
around.
Once upon a time…
Later in the season, Chemis left Equazius for a trip to visit her
sisters who were also witches. While she was gone Steudint ran
to the towns and told all the people who had been hiding the
ingredients to quickly bring them to the river.
As the people gathered on each side of the river, each holding a
precious ingredient, Steudint told them that they must put the
ingredients into the river. But, he said, if the ingredients were
not placed in the river from each side in equal amounts the
entire country would be thrown into chaos forever!
Help the people of Equazius to balance the ingredients of the
potion. Here are the sets of ingredients Steudint had given
them. You can add new sets, but you can’t separate any set and
no set can cross the river.
1 CH4 + 2 O2  1 CO2 + 2 H2O
Here’s the what they did. Are the people saved?!
Hint: Count the ingredients, not the sets.
How does this formula relate to the “equation” demonstrated
below?
1 CH4 + 2 O2  1 CO2 + 2 H2O
Balancing
Balancing
Equations:
Equations
LEARN
Step 1: Count the atoms in the reactants and in the products.
Mg + O2  MgO
1
2
Magnesium is balanced…but Oxygen is not.
1
1
Balancing Equations: LEARN
Step 2: Choose a coefficient to add more of the element that is
not balanced.
Mg + O2  2 MgO
1
2
1
2
2
1
The number you added indicating more than one atom of a
particular element in an equation is called a coefficient.
Let’s continue…Now oxygen is balanced, but magnesium is not.
Balancing Equations:
LEARN
LEARN
Step 3: Keep the first coefficient. Re-evaluate and now choose a
coefficient that balances the second element.
2 Mg + O2  2MgO
21
2
2
2
Congratulations! Now everything is balanced!
Balancing Equations: PRACTICE
Ca +
__F
 CaF2
Check Yourself
Ca +
2
__F
 CaF2
Balancing Equations: LEARN
Sometimes equations require a little more thought.
HINT: Find the lowest common multiple of 3 and 2 to figure
out how many of each ion you need.
2 Al3 + 3 O2  Al2O3
2x3=6
3x2=6
Balancing Equations: PRACTICE
Practice: Write the formula for combining sodium and oxygen.
Na + O2  Na2O
Check Yourself
4Na + O2  2Na2O
Polish your skill…Let’s play ChemBalancer.
http://funbasedlearning.com/chemistry/chemBalancer/default.htm
MORE PRACTICE ONLINE AT http://education.jlab.org/elementbalancing/
READY?…Balance the following equation.
Li + H2O  LiOH + H2
Answer:
2Li + 2H2O  2LiOH + H2
EOG L6 & L11
Matter and Energy in Chemical Reactions
Reactant
Reactant
Reactants
ENTER the
reaction.
Endo – inside
Exo – outside
Energy is
absorbed or
released by
the reaction.
Products are
PRODUCED by
the reaction.
EXOthermic Reaction = RELEASES energy
Reactant
Reactant
Reactants
ENTER the
reaction.
EXOTHERMIC
Energy is
RELEASED by
the reaction.
Products are
PRODUCED by
the reaction.
ENDOthermic Reaction = ABSORBS energy
Reactant
Reactant
Reactants
ENTER the
reaction.
ENDOTHERMIC
Energy is
ABSORBED by
the reaction.
Products are
PRODUCED by
the reaction.
Exothermic Reaction = Releases Energy
ACTIVATION ENERGY = energy required
ENERGY
to cause the reaction to occur.
Energy
RELEASED
TIME
Endothermic Reaction = Absorbs Energy
ACTIVATION ENERGY = energy required
to cause the reaction to occur.
Energy
ENERGY
ABSORBED
TIME
Chemical Reactions and Catalysts
Catalysts are special molecules that aid in making chemical
reactions happen but are not used up themselves
Catalysts reduce the activation energy!
ACTIVATION ENERGY = energy required
to cause the reaction to occur.
ENERGY
Activity:
The marble,
the cup, and
the spoon.
TIME
Any
Questions?
ACT L11
Acids, Bases and pH
PHET acid-base-solutions_en
The pH Scale ranks the
amount of hydrogen ions
(H+) that are in a
solution.
pH Scale
0
1
H+
Gastric juice,
2 lemon juice
H+
–
H+ OH
OH– H+
H+ H+
H+
3 Vinegar, beer,
wine, cola
H+
4 Tomato juice
Acidic
solution
More hydrogen ions make
the solution acidic.
5
Black coffee
Rainwater
6 Urine
OH–
OH–
–
Less hydrogen ions make
the solution basic.
Battery acid
H+ H+ OH
OH– OH– +
H
H+
H+
Neutral
solution
Neutral
[H+] = [OH–]
Saliva
7 Pure water
Human blood, tears
8 Seawater
9
10
Acidity and basicity are
indicated by pH or litmus
paper.
OH–
Milk of magnesia
OH–
OH–
H+ OH–
–
OH–
OH
OH–
+
H
Basic
solution
11
Household ammonia
12
Household
13 bleach
Oven cleaner
14
How do you neutralize an
ACID spill?
ACID
BASE
Indicator = changes color in response to change in pH
ACT L12
pH Interactive Lab
http://splash.abc.net.au/res/i/L5814/index.html
STATES OF MATTER
Changes in state = melting, freezing, evaporation, condensation,
sublimation, deposition.
ACT L13
BEHAVIOR OF GASES
Kinetic Molecular Theory (of Gases)
1. constant, random motion
2. continuous movement in
straight line until collision
3. mostly empty space
4. no attraction forces
5. elastic collisions (bounce)
6. kinetic energy depends on
temperature
Quizlet.com
TJCA 8th Unit 2b Chemical
Bonds and Reactions
ACT L14
I’m diggin’ for
questions!
Got any?
Let’s Get Chemical!
Use the materials you have been given to design and perform tests
showing each of the following physical characteristics of matter.
Answer the questions and turn in your worksheet.
Physical Property
Materials to Use
Conductivity
wire, battery
Magnetism
magnets
Malleability
ball of foil
Solubility
salt, water
Density of Liquids
orange juice, tomato juice, pipet, clear cup
pH
lime juice, detergent, litmus paper
Density of an irregular object marble, graduated cylinder, balance, water
Density of regular object
block, balance, ruler