ELEMENTS, COMPOUNDS,
AND MIXTURES
A Meteorite may travel 400 M km to
reach Earth.
BUT, the particles of iron in a meteorite,
a steel spoon and braces are all alike!
Elements, the Simplest
Substances
• Element: a pure substance that
CANNOT be separated into simpler
substances by physical or chemical
means.
• Examples: Iron, Gold, Mercury,
Nickel, Cobalt.
Elements, the Simplest
Substances
• A pure substance: contains only
ONE TYPE of particle.
• These particles are called ATOMS!
• Example: Every atoms in a 5 g
nugget of gold is like every other
atom of gold!
Properties of Elements
• PHYSICAL
PROPERTIES:
• Boiling Point
• Melting Point
• Density
• Texture
• Color
• CHEMICAL
PROPERTIES:
• Reactivity with
Acid
• Flammable
Identifying Elements by
Their Properties
• Elements can be identified by their
properties.
• Example: Look on page 57 – Figure
2. What element has a Melting
Point of 1,535 degrees Celsius and
combines slowly with O in the air?
• ANSWER:_________________
Classifying Elements by
Their Properties
• Elements are grouped into
categories by the properties they
share.
• 3 Major Categories:
• METALS: Shiny, good conductors
• NONMETALS: Dull, poor conductors
• METALLOIDS: Have properties of
both metals and nonmetals! 
Compounds
• Compounds: 2 or more elements that
are CHEMICALLY combined!
• They combine through a chemical
reaction.
• In Figure 1: page 60 –
Mg + O = MgO
• Magnesium Oxide (MgO) is a NEW
substance with different characteristics!
Examples of Compounds
•
•
•
•
•
•
Table Salt: NaCl
Water: H2O
Vinegar: CH3COOH
Carbon Dioxide: CO2
Baking Soda: NaHCO3
Sugar: C12H22O11
Compounds vs Elements
• COMPOUNDS
• Salt: a safe
seasoning for you
to eat.
• ELEMENTS
• Sodium: soft,
silvery white metal
that reacts
violently with
water.
• Chlorine:
poisonous,
greenish yellow
gas
Breaking Down
Compounds
• Compounds can be broken down into
elements or simpler compounds.
• HOW??? – By Chemical Changes!
• Example: Carbonic Acid (gives soda
“fizz”) breaks down into Carbon Dioxide
and Water just when you open a soda.
• Carbon Dioxide and Water can be broken
down by chemical changes.
MIXTURES
• Mixture: a combination of two or
more substances that are NOT
chemically combined.
• NO chemical change happens when
a mixture is made.
• EX: Pizza, Chex Mix, Lucky
Charms, Salad.
Solutions
• Solutions: a mixture that appears
to be a single substance. It is
composed of particles of two or
more substances.
• SOLUTE + SOLVENT = SOLUTION
• Is Dissolved + Dissolves It
• Hot Cocoa Mix + Water = Hot Cocoa
Concentration of
Solutions
• Concentration: a measure of the
amount of solute dissolved in a
solvent.
• Concentrated: TOO much solute
• Dilute: TOO little solute
Suspensions
• Suspension: a mixture in which
particles of a material are dispersed
throughout a liquid or gas but are
large enough to settle out.
Colloids
• Colloid: a mixture in which the
particles are dispersed throughout
but are not heavy enough to settle
out.
• The particles in a colloid are much
smaller than in a suspension.
• Examples: Milk, Mayonnaise, Stick
Deodorant, and Jello
I Can Statements…
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•
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I
I
I
I
I
can
can
can
can
can
tell
tell
tell
tell
tell
you
you
you
you
you
that
that
that
that
that
an element is…
a compound is…
a solution is…
a suspension is…
a colloid is…