ELEMENTS, COMPOUNDS &
MIXTURES
Composition of Matter
Pure Substances
• Materials are made of a pure substance or a
mixture of substances.
• A pure substance, or simply a substance, is a
type of matter with a fixed composition.
• A substance can be either an element or a
compound.
Classification of Matter
 Matter- anything that
has mass and takes up
space
 Atom- smallest unit of
matter
Types of substances
 Elements
 Most simple, pure substance,
one type of atom present
 O2, Na, Fe, N2
Composition of Matter
1
Elements
• About 90 elements are found
naturally on Earth.
• More than 20 others have been made in
laboratories, but most of these are
unstable and exist only for short periods
of time.
Types of substances
 Compound  1. Composed of 2 or MORE
different atoms (combined by
chemical reaction)
 Sugar- C6H12O6
 Salt- NaCl
 2. Will exhibit different
properties from the elements
that make them up
Classification of Matter
 Mixtures
 1. Made of more than one kind
of material (several compounds,
compounds and elements, or
several elements)
Classification of Matter
 Mixtures
 1. Made of more than one kind
of material (several compounds,
compounds and elements, or
several elements)
 3. 2 types:
 Heterogeneous
 Homogeneous
Atom, Element, Compound,
Molecule??
 REMEMBER:
 An atom is the smallest unit of matter
 An element is made of ONE TYPE of ATOM
 A compound is a chemical combination of
two of more DIFFERENT types of atoms
What is a Molecule
 A molecule is the smallest unit of a




compound that retains all properties of that
compound.
Example: glass of distilled water
One water molecule is that smallest unit of
that compound
SOME atoms cannot exist as an individual in a
sample of matter.
EXAMPLE: oxygen, nitrogen, chlorine
Representations of Atoms,
Molecules and Compounds
Atom- represented by a circle
that is ONE color OR ONE pattern
Compound- represented by TWO or
more DIFFERENT colored circles,
DIFFERENT size circles, OR
DIFFERENT patterns in the circles
But are ATTACHED together
Representations of Atoms,
Molecules and Compounds
cont.
Molecule – Can be represented
By two circles the same color,
pattern, or two or more circles
that DIFFERENT colors, sizes
or patterns.
Element or compound?
 Look at the pictures below - is it an element
or a compound?
Element
Element
Compound
Element
Compound
Chemical Symbols
A Chemical symbol is
an abbreviation of
the name of an
element.
How are they
written?
 Capital letter if only
one letter.
 Only first letter
capital if more than
one letter
Element
Oxygen
Chemical
Symbol
O
Nitrogen
N
Hydrogen
H
Sodium
Na
How to read a formula
This is a subscript.
H 20
It tells us how many atoms of
that element exist in one
molecule of that compound.
Hydrogen is made of 2 H
atoms and 1 O atom.
Compounds Have Formulas
The formula tells you
1. elements in the
compound
2. # of atoms of each
element in the
compound.
Chemical Formulas
 Each symbol in a formula represents an
element.
 If only one atom of an element is present
in the compound, no subscript is used.
- If more than one atom of an element is
used, then the symbol is followed by a
number called a subscript.
Chemical Formulas - Examples
 Calcium Carbonate (chalk) – CaCO3
 Sodium Chloride (salt) – NaCl
 Acetysalicylic acid (aspirin) – C9H4O8
 Acetic acid (vinegar) – C2H4O2
Types of substances
Heterogeneous
Mixtures
 1. Not the same throughout
 2. Large easily seen particles
that can be separated out
 3. Heterogeneous liquid
mixtures known as
suspensions Settles after
standing
 4. Tacos, salad, italian
dressing, pebble/sand mixture
Heterogeneous Mixtures
Heterogeneous
Mixtures
 6. Colloids
 Won’t settle out
 Cloudy-Scatters light
 Particles mix, don’t dissolve
 Milk, lotion, toothpaste
Types of substances
Homogeneous
Mixtures
 1. Appears same throughout
 2. Well mixed
 3. Won’t settle upon standing,
 4. Tiny unrecognizable particles
 5. Type:
 Solutions
Homogeneous Mixtures
 Homogeneous 
Mixtures
7. Solutions
a) One substance dissolved
in another
b) Tiny particles can’t be
seen
c) Best mixed
d) Clear or transparent- light
passes right through
e) Bottled water, apple juice
air
Homogeneous Mixtures
Homogeneous
Mixtures

8. Metal Solutions
a) Alloys- solid metal
solutions
b) Gold= copper and gold
c) Brass= copper and zinc
d) Sterling silver= silver
and copper
Graphic Organizer
 Create a graphic organizer to show the
relationship between the following terms:
 elements
 compounds
 homogeneous mixtures
 heterogeneous mixtures
 suspensions
 colloids
 solutions
What types of substances are on
the front counter? Label each
with
the correct substance name
 Element?




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Compound?
Heterogeneous Mixture?
Heterogeneous Mixture: Suspension?
Homogeneous Mixture: Solution?
Homogeneous Mixture: Colloid?
Homework
 Write the following assignment into your
agenda:
 E, C, M Worksheet