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CHAPTER 14, 16 & 18
WHAT IS CHEMISTRY?
Balloon Demonstration
(Conceptual Integrated Science Explorations: p.259)
Hypothesis – what will happen when you fill the
balloon with the fragrance?
1. Get balloon & smell it – record
2. Fill balloon with fragrance & then fill with air–
smell & record
3. Answer questions 1 & 2 under Analyze &
conclude on pg 259

Questions
Open your BOOK to page 273 and answer
questions:
 3-7

Bill Nye the Science Guy!
ATOMS
http://www.youtube.com/watch?v=Ez0Poi1
YJS0&feature=endscreen&NR=1 (Full video
- 22:11)
 http://www.youtube.com/watch?v=cnXV7P
h3WPk (video clip - 6:37)

Chapter 14:
The Atom
14.1 & 14.2:
The Atom

Submicroscopic (smaller than microscope level!)
particles. Teeny-tiny basic units that make up
stuff

1 grain of sand contains around 125 MILLION
TRILLION atoms.

The # of atoms in a baseball is equivalent to the #
of ping-pong balls that could fit inside Earth

There are more than 100 different kinds & are
listed on the periodic table
Parts of an Atom

Atoms are made up of EVEN SMALLER
particles

Subatomic particles:
– Protons (positive charge)
– Neutrons (no charge)
– Electrons (negative charge)
The Atom
Atomic Nucleus & Electrons

Atomic Nucleus - core of atom, makes
up most of atom’s mass, consists of
PROTONS & NEUTRONS.

ELECTRONS buzz around the empty
space surrounding the nucleus. Negative
charge
14.3: Protons & Neutrons
PROTON– heavy particle in the nucleus
that’s positively (electric) charged. Has SAME
quantity but OPPOSITE charge of electron
 NEUTRON – same mass as proton, but no
charge, also found in the nucleus.
 Nucleons - general term for subatomic
particles in the nucleus: protons & neutrons

Atomic Number
= to the number of
PROTONS in atomic nucleus
 Order of elements
 Ex:

– Hydrogen (H) has 1 proton
per atom, the atomic number
– Helium (He) has 2 protons in
nucleus & atomic number is 2

Which element does the
diagram represent?
Nitrogen!
Which atom does this
diagram represent?
OXYGEN!
Periodic Table of Elements
pages 264-266 & 16.6
ELEMENTS




Any material made of only one type of
atom
Elements are the building blocks of
matter
There are 115 known elements today, 90
which occur naturally
All elements are listed in a chart called
the PERIODIC TABLE
ELEMENTS (Cont)

Each element has a unique symbol
– The first letter is always capitalized, the
second letter is always lower case
 Fluorine is F, not f
 Cobalt is Co, not CO (which is carbon monoxide)
 Oxygen is O

The smallest unit of an element is the
atom
Atomic Symbol

Each element has a unique symbol
– The first letter is always capitalized, the second
letter is always lower case
 Fluorine is F, not f
 Cobalt is Co, not CO (which is carbon monoxide)
 Oxygen is O
Groups
Vertical column of
table
 Also called a family
 All elements in the
same Group have
similar properties
Ex: Noble Gases He, Ne, & Ar are all
gases

Groups cont’d
Group Names
Group 1: Alkali Metals
 Group 2: Alkaline-earth Metals
 Group 3 – 12: Transition Metals
 Group 13 – 15: No Common Name
 Group 16: Chalcogens
 Group 17: Halogens
 Group 18: Noble Gases

Periods


Horizontal row
Across any period
(horizontal row) the
properties of
elements gradually
change – called a
periodic trend

Trends repeat from
one row to the next
Periods

Ex: Atom Size - atoms get smaller as you
move from left to right
BIGGER to smaller
14.4: Mass Number

Mass Number: the total number of protons
and neutrons (total number of nucleons)
Hydrogen-1
Hydrogen-2
Hydrogen-3
14.4: Isotopes

Isotopes: any member of a set of atoms of
the same element whose nuclei contain the
same number of protons but different numbers
of neutrons


mass number – atomic # = # of neutrons
Ex: Iron-56
55
2
6
Fe
Isotope Examples

Iron-56 & Iron-55
How many neutrons are in each? (Hint: See PT)
 Iron-56: 56 – 26 = 30 neutrons
 Iron-55: 55 – 26 = 29 neutrons

7
3
Li isotope
How many neutrons are in lithium?
7 – 3 = 4 neutrons

If an atom has 6 electrons, 8 neutrons, and 6
protons, what is the mass number? What is the
element?
 mass number = 14, the element is Carbon
Isotopes
Use a Periodic Table to complete the following table
Isotope
Mass
Number
Isotope
Notation
Protons
Electrons
Neutrons
Hydrogen-1
Chlorine-?
19
Nitrogen-14
Potassium-40
Arsenic-?
Gold-197
42
Isotopes
Answers
Isotope
Hydrogen-1
Chlorine-36
Nitrogen-14
Potassium-40
Arsenic-75
Gold-197
Mass
Number
1
36
14
40
75
197
Isotope
Notation
1H
1
36
Cl
17
14
N
7
40
K
1
9
75
33 As
197
79
Au
Protons
Electrons
Neutrons
1
1
0
17
17
19
7
7
7
19
19
21
33
33
42
79
79
118
Isotopes
Use a Periodic Table to complete the following table
Isotope
Mass #
Isotope Atomic #
Notation
Protons
Electrons
Neutrons
Oxygen-16
Calcium-40
48
36
Copper-64
34
15
45
15
Isotopes
Answers
Isotope
Oxygen-16
Calcium-40
Krypton-84
Copper-64
Selenium-79
Phosphorus-30
Mass #
16
40
84
64
79
30
Isotope Atomic Protons
Notation #
16O
8
40
Ca
20
84
36Kr
64
2
9
Cu
79
34 Se
30
15 P
Electrons
Neutrons
8
8
8
8
20
20
20
20
36
36
36
48
29
29
29
35
34
34
34
45
15
15
15
15
Atomic Mass

Atomic Mass: The sum of the masses of
all the atom’s electrons, protons and
neutrons
14.5: Electron Shells
Within the atom, electrons
behave as though they are
arranged in shells.
 Each shell can hold a certain
number of electrons

– Innermost shell: 2
– Shells 2-3: 8 each
– Shells 4-5: 18 each
– Shells 6-7: 32 each
Bohr’s Shell Model
 Make
a shell model for the following
atoms:
–Fluorine
–Neon
–Chlorine
–Argon
–Iron
–Arsenic
Valence Electrons
Electron in outermost
shell of an atom
 Atoms combine to
form molecules by
valence electrons
 “combining power” of
an atom

Chapter 16:
Elements of Chemistry
16.1: Chemistry:
The Central Science

Chemistry is the study of matter and the
transformations it can undergo.

What is matter?
– Anything that has mass and takes up space.
IMPORTANCE OF CHEMISTRY

Chemistry is all around you.
– Air you breathe
– Food you digest
– Clothes you wear
– Textbook you read

Chemistry is often said to be the central
science.
Syringe Activity


1.
2.
3.
4.
Materials: Syringe, cup of water, mini marshmallow, (rubber stopper)
Do the following & Record observations
Double the pressure
Quadruple the pressure
Reduce volume in half – let go of plunger
Start @ 0mL, block end & try to lift plunger all the way out
Indicates atmospheric pressure
Add marshmallow. Pressurize it as much as possible.
6. Start with plunger close to marshmallow. Cover end and try to lift plunger.
7. Remove marshmallow. Completely fill syringe with water. Compress syringe
Why was it hard to quadruple pressure?
What was happening to the air particles inside as you tried to add pressure?
Why was it so hard to lift the plunger out of the syringe?
Why did the marshmallow respond as it did to the changes in pressure?
Why can’t you compress water?
5.
16.2: The Submicroscopic World

Submicroscopic – beyond the microscopic
level. Atoms & molecules

Molecules - some atoms link together to
form larger but still incredibly small units
of matter called molecules
Phases of Matter

Liquid – matter that has a definite volume but
no definite shape, assumes shape of container

Solid – matter that has definite shape & volume

Gas – matter that has neither definite volume
nor definite shape, fills any space available
PHASES OF MATTER
Complete the following chart:
SOLID
LIQUID
SHAPE
VOLUME
Arrangement of
Particles
Interaction between
Particles
Movement of
Particles
Example
Copyright © 2005 by Pearson Education, Inc.
Publishing as Benjamin Cummings
GAS
PHASES OF MATTER
Complete the following chart:
SOLID
LIQUID
GAS
SHAPE
Definite shape
Shape of container
Shape of container
VOLUME
Definite volume
Definite volume
Volume of container
Arrangement of
Particles
Fixed, very close
Random, close
Random, far apart
Interaction between
Particles
Very strong
Strong
Essentially none
Movement of
Particles
Very slow
Moderate
Very fast
Example
Ice, salt, iron
Copyright © 2005 by Pearson Education, Inc.
Publishing as Benjamin Cummings
Water, oil, vinegar
Water vapor, helium,
air
WATER AND ITS STATES OF MATTER
16.3: Changes of Phase
 In
order to
change the phase
of a substance,
you must either
add heat or
remove heat
Change of Phase
Melting: Solid to liquid
 Boiling: Liquid to gas
(beneath the surface)
 Evaporation: Liquid to gas
(surface)
Boiling & Evaporation

Melting
– The above 3 require input of
heat energy
Condensation
Condensation: Gas to liquid
 Freezing: Liquid to solid

– The above 2 release heat
energy
Freezing
Change of Phase Diagram
16.4: Physical & Chemical
Properties & Changes
PHYSICAL PROPERTIES
Any physical attribute of a substance such as
color, density, texture, hardness, & phase
 Each substance has unique physical properties
 Examples

– Sulfur appears as a yellow powder
– The boiling point of water is 100 oC
– Carbon monoxide is odorless
PHYSICAL CHANGES

Change in substance’s physical property
but doesn’t change the composition
– Examples include:
 Any change in the state of matter (e.g. freezing or
boiling water)
 Sawing wood
 Crushing a tablet
 Bending a wire
 Dissolving salt in water
CHEMICAL PROPERTIES

Describe ways pure substances behave
when interacting with other pure
substances.

Examples
– Iron reacts with oxygen to form rust.
– Platinum does not react with oxygen at room
temperature.
CHEMICAL CHANGES

Changes the identity of the substance as
the chemical composition changes.
– Also called chemical reactions

Examples:
– Tarnishing of silver
(Ag forms AgS)
– Rusting of iron
(Fe forms Fe2O3)
16.5: Determining Physical &
Chemical Changes
Molecules:
Physical
Chemical
Change in
New
physical
material or
appearance? same after
returning
to original
conditions?
New
Examples:
material
that has its
own
unique set
of physical
properties?
16.5: Determining Physical &
Chemical Changes
Molecules:
Physical
Chemical
Molecules
are the
same as
started with
Original
molecules
have been
destroyed &
new ones
are in place
Change in
New or
physical
same
appearance? material
after
returning
to original
conditions?
yes
yes
same
new
New
Examples:
material
that has its
own
unique set
of physical
properties?
no
yes
•Ice melting
•Potassium
chromate
•Iron turning
to rust
•Ammonium
dichromate
CHEMICAL REACTIONS


Are the same as a chemical change
Are expressed using chemical equations.

Rusting of iron:
4 Fe + 3 O2  2 Fe2O3 (rust)
reactants
products
Meaning:
Four atoms of iron react with three molecules
of oxygen to form two molecules of rust
The Law of Conservation of
Matter/Mass


Matter can neither be created nor destroyed
in an isolated system
Brain Pop: Chem equations & Conservation of Matter/Mass
CHEMICAL REACTIONS (Cont)
Zn + 2 HCl
Zinc
hydrochloric acid

ZnCl2 + H2
zinc chloride
hydrogen gas
Meaning:
One atom of zinc reacts with two
molecules of hydrochloric acid to produce
one molecule of zinc chloride and one
molecule of hydrogen gas.
How to Balance Chemical Equations
1. Write the unbalanced equation.



Chemical formulas of reactants are listed on the left-hand side
Products are listed on the right-hand side
Reactants and products are separated by putting an arrow between them
to show the direction of the reaction.
2. Balance the equation.




Apply the Law of Conservation of Mass to get the same number of atoms
of every element on each side of the equation.
Start by balancing an element that appears in only one reactant
and product.
Once one element is balanced, proceed to balance another, and another,
until all elements are balanced.
Balance chemical formulas by placing COEFFICENTS in front of them. DO
NOT add subscripts, because this will change the formulas.
Practice Balancing Equations
1
__Fe + __Cl2  __FeCl3
2
__Al + __O2  __Al2O3
3
__CH4 + __ O2  __ CO2 + __ H2O
4
__ Na + __ Cl2  ___ NaCl
5
__ N2 + __ H2 ➜ ___ NH3
6
__ Al + __ HCl ➜ __ AlCl3 + ___ H2
Practice Balancing Equations:
ANSWERS

_2_Fe + _3_Cl2  _2_FeCl3

_4_Al + _3_O2  _2_Al2O3
Balancing Chemical Equations
Modeling Clay Activity
Use modeling clay to represent each element to
balance the chemical equations on the chart.
 Example:

– Fe + Cl2  FeCl3
 Fe (iron) = YELLOW clay
 Cl (chlorine) = BLUE clay
Balancing Chemical Equations
Modeling Clay Activity
Use modeling clay to represent each element to
balance the chemical equations on the chart on
the next slide.
 Example:

– Fe + Cl2  FeCl3
 Fe (iron) = YELLOW clay
 Cl (chlorine) = BLUE clay
Balancing Chemical Equations
Modeling Clay Activity
Make the
equations on
your desk
H 2 + O 2  H2O
H2O2 H2O + O2
Na + O2  Na2O
N2 + H2  NH3
P4 + O2  P4O10
Fe + H2O 
Fe3O4 + H2
C + H2  CH4
Na2SO4 + CaCl2
CaSO4 + NaCl
C2H6 + O2 
CO2 + H2O
Al2O3  Al + O2
Reactants
(Start)
Products
(Start)
Balanced Equation
Reactants
(Final)
Products
(Final)
CLASSIFICATION OF MATTER
ELEMENTS
(you have these notes already)




Any material made of only one type of
atom
Elements are the building blocks of
matter
There are 115 known elements today, 90
which occur naturally
The periodic table displays the elements
ELEMENTS (Cont)
(you have these notes already)

Each element has a unique symbol
– The first letter is always capitalized, the
second letter is always lower case
 Fluorine is F, not f
 Cobalt is Co, not CO (which is carbon monoxide)
 Oxygen is O

The smallest unit of an element is the
atom
COMPOUNDS

Atoms of different elements bond to one another
to make a compound
– NaCl (table salt)
 Contains sodium (Na) and chlorine (Cl)
 NaCl is the chemical formula
– H2O (water)
 Contains 2 atoms of hydrogen (H) and 1 atom of oxygen (O)
 H2O is the chemical formula

Elements in compounds are combined in a
definite ratio
– H2O is water but H2O2 is hydrogen peroxide
COMPOUNDS (cont)

Are H2 and O3 considered elements or
compounds? Why?
Heterogeneous Mixture
The different
components can be
seen as individual
substances
 Different parts are
visible
 Ex: Pulp in orange
juice, sand in water, oil
& water, pizza

Homogeneous Mixture
Have same
composition
throughout
 Can’t see separate
parts
 Ex: Air, blood, fog,
salt water

CLASSIFICATION OF MATTER
Classify the following as an element,
compound, homogeneous mixture, or
heterogeneous mixture.
a.
b.
c.
d.
e.
f.
Fog
Gasoline
Helium
Sulfuric acid (H2SO4)
Orange juice from squeezed oranges
H2
PRACTICE PROBLEM
Identify the following properties and
changes as physical or chemical.
a. The copper sheets that form the “skin” of the
Statue of Liberty have acquired a greenish
coating over the years.
b. Carbon appears as black powder.
c. Adding food coloring to water.
d. Wood burns in air.