Alief ISD Chemistry STAAR Review
Reporting Category 1: Matter & Periodic Table
C.4.A
Differentiate
between
physical and
chemical
changes and
properties.
Physical & Chemical Properties
Properties of substances can be classified as either physical or chemical.
A physical property is a quality or a condition of a substance that can be observed or measured
without changing the substance’s composition. Examples: shape, length, mass, volume, melting
point, boiling point, state of matter, color, hardness, density and solubility. Physical properties
can be used to identify a substance.
A chemical property DESCRIBES the ability of one substance to change into a different
substance. A chemical property differs from a physical property in that we can observe it ONLY by
changing the composition of a substance.
Examples: reactivity, flammability, heat of combustion, electronegativity, and ability to oxidize.
Property
Physical
Chemical
Description
Can be observed without
changing the substance into a
different substance
Examples
Describing substances boiling
point, color, density, solubility
Can be observed when a
substance changes into a
different substance
Describing substances
reactivity with oxygen, or its
flammability, or its toxicity
Physical & Chemical Changes
A physical change is a change that does not alter (or change) the chemical identity of a
substance. The substance that exists before the change still exists after the change.
Examples: cutting, crushing, or breaking into smaller pieces…also, phase changes are classified
as physical changes; such as melting, evaporating, freezing…etc.
A chemical change occurs when one or more substances change into one or more DIFFERENT
substances. A substance present before the change happens is called a reactant; a substance
produced as a result of the change is called a product. In a chemical change, the products have
different chemical and physical properties from those of the reactants. Example: iron reacts with
oxygen to product iron oxide (“rust”)
4 Fe
+
3O2 
2Fe2O3
How can you recognize a chemical change? Some signs are: formation of a gas, a change in
color or odor, a change in temperature, the release of light or sound, and the formation of a
precipitate.
Change
Description
Examples
Change is size, shape, or
state; remains the same
substance
Freezing water, shredding
paper, melting wax
New substance is made;
bonds between atoms are
made or broken; often see a
color change, temperature
change, or the formation of
gas or precipitate (solid)
Burning wood, iron rusting
Physical
Chemical
C.4.B
Identify
extensive and
intensive
properties.
Types of Properties
Physical and chemical properties of matter can be classified as either intensive or extensive.
What is an intensive property?
An intensive property is a property that IS NOT dependent on the amount of a substance.
Different amounts of a substance will have the same intensive properties. Example: Pure water
0
will always boil at 100 C no matter what volume you start with. Boiling point is an intensive
property. Also, the density of pure water at room temperature will always be 1 g/mL no matter how
much water you have. Density is an intensive property. The more intensive properties that are
known for a given substance, the easier it is to identify the substance.
What is an extensive property?
An extensive property is one that changes with the amount or size of a substance. Example:
Water’s mass WILL change depending on the amount of water you have. Mass is an extensive
property. Knowing an extensive property of a substance WILL NOT help identify it. Why?
Extensive Properties and Intensive Properties
Extensive properties
Intensive properties
•
Dependent on the amount of a
•
Not dependent of the amount of a
substance
substance
•
Not dependent on the identity of a
•
Dependent on the identity of a
substance
substance
•
Examples: mass, length, volume,
•
Examples: density, boiling point,
energy
reactivity, solubility, specific heat,
hardness
C.4.C
Compare solids,
liquids, and
gases in terms of
compressibility,
structure, shape,
and volume
States of Matter and Properties
Property
Compressible
Shape
Solid
Basically no
Fixed/rigid
Volume
Structure
Fixed (constant)
Forces keep particles
in a rigid structure
Liquid
Basically no
Takes container’s
shape
Fixed (constant)
Intermolecular forces
keep particles
together but allow
movement
Gas
Yes
Fills up the whole
space of container
Changes
Particles move freely,
virtually no forces
C.4.D
Classify matter
as pure
substances or
mixtures through
investigation of
their properties.
Matter
Matter: anything that takes up space and has mass
This car represents matter
because it has mass and is made
from different materials
Homogeneous:
Composition-same all the way through
Solution
Heterogeneous:
Composition-different & can see
the different parts
Pure Substance
Mixture that is clear
and you can’t see the
parts (dissolved)
Composed of elements and
has a constant composition
Mixture
Composed of different
parts that can easily be
seen
[not chemically bonded]
Elements
hot tea
hot tea
Composed of elements
chemically bonded; in set ratio
type of atom
and composition
This is a GOLD coin. Gold is
an element on the periodic
table. Au
C.5.A
Explain the use
of chemical and
physical
properties in the
historical
development of
the Periodic
Table.
Compounds
Basic part of matter;
Made up of only one
This is WATER. Water is composed of
hydrogen and oxygen in the ration of 2hydrogen atoms to every 1-oxygen atom
How were chemical and physical properties used in the development of the
periodic table?
As scientists learned how to isolate elements from compounds, the number of known elements
increased rapidly in the early 1800s. Scientists looked for patterns and similarities in the
properties of elements in order to classify the growing number of discovered elements.
Mendeleev organized known elements that shared similar chemical and physical properties
(like Li, Na, and K which react violently with H2O to make H2) into the periodic table. The periodic
table is an arrangement of elements in which the elements are separated into groups based on a
set of repeating properties. Mendeleev arranged the elements in his periodic table in order of
increasing atomic mass.
Over time, other scientists added to his work to create the periodic table now ordered by increasing
atomic number.
Vocabulary you will need to know to understand the organization of Periodic
Table:
Vocabulary word
Valence electrons
Definition
Electrons in an atom’s
outermost orbital
shell; can be gained,
lost. Or shared in a
chemical reaction
Picture
How many valence electrons are shown in the picture
above?
Periodic table
Chart of elements
ordered by atomic
number and grouped
by number of valence
electrons; chemical
and physical
properties vary
predictably in the table
(trends exist
horizontally and
vertically)
Row or period
Elements are in order
of increasing atomic
number; atomic
number = number or
protons = number of
electrons (if neutral)
Chemical elements in the first period:
1 2
H He
Chemical elements in the second period:
3 4 5 6 7 8 9 10
Li Be B C N O F Ne
Etc….
Column or group
(family)
Elements in a group
have the same
number of valence
electrons and have
similar physical and
chemical properties.
Group 18 called Inert or Noble Gases
What is Group 1 called? Group 17?
C.5.B
Use the Periodic
Table to identify
and explain the
properties of
chemical
families,
including alkali
metals, alkaline
earth metals,
halogens, noble
gases, and
transition
metals.
Metals
Good conductor,
ductile, malleable,
shiny; located on left
of the zigzag line on
PT
Nonmetals
Poor conductor, brittle
dull; located on right
of the zigzag line of
PT
Metalloids (semimetals)
Conductor under
some conditions;
located on top and
bottom of zigzag line
What are the main chemical families on the periodic table?
Periodic Table of Elements
+1
0
Alkali Metals
Noble Gases
+2
-1
Alkaline Earth Metals
Halogens
Oxidation #’s vary
Transition Metals
Description of Main Families of the Periodic Table
Main Families
Alkali Metals
Alkaline Earth Metals
Halogen
Noble Gases/Inert Gases
Transition Metal
Description and Oxidation Number(s)
Very reactive metal; wants to lose 1 electron; +1
Reactive metal; wants to lose 2 electrons; +2
Reactive nonmetal; “salt-formers”; wants to gain 1 electron; -1
Inert (not readily reactive) nonmetal; has full outer shell (8
valence electrons except He has 2); 0
Metal in table’s center; has partially filled shell and variable
1+
2+
oxidation numbers (like Cu or Cu )
Oxidation number: represents electrons gained or lost when forming compounds
Anion: negative charge; when atoms gains electrons example: anion F- (oxidation # -1
because it gains one electron)
2+
Cation: positive charge: when atoms lose electrons example: cation Ca (oxidation # +2
because calcium loses 2 electrons)
C.5.C
Use the Periodic
Table to identify
and explain
periodic trends,
including atomic
and ionic radii,
electronegativity,
and ionization
energy.
Trends in the Periodic Table
Property
Atomic radius
Ionic radius
Electronegativity
Ionization energy
Description and Trend Direction (s)
As you move down a family atomic radius increases; as you move from left
to right the atomic radius decreases.
For anions (gains electrons) the ionic radii increases; for cations (lose
electrons) the ionic radii decreases
Atom’s tendency to attract electron’s; Electronegativity increases as you
move left to right (excluding noble gases); Electronegativity decreases as
you move down a family
Energy needed to remove an electron from an atom; Ionization energy
increases as you move left to right; Ionization energy decreases as you
move down a family.