The
Classification of
Matter
Atoms, Elements,
Molecules and
Compounds
PURE SUBSTANCE
Something that can not be
broken down into simpler matter
using physical methods.
There are two types of
substances…
Elements & Compounds.
ELEMENTS
 Are the simplest kind of
pure substance.
 There are ~ 110 elements,
each made of a different type
of atom (periodic table).
 Each element has a name and symbol.
Not all elements are equally
common.
Most elements can
exist as a single
atom (Fe, Cu):
But some elements
(mostly gases)
usually exist as
diatomic molecules
(groups of 2
atoms).
Diatomic Gases
Hydrogen H2
Nitrogen N2
Oxygen O2
Fluorine F2
Chlorine Cl2
Bromine Br2
Iodine I2
Allotropes
Different structural forms of the same
element.
Oxygen has 3 allotropes:
O
Monatomic
Oxygen
(Single Oxygen
Atom)
O2
Diatomic
Oxygen
Molecule
O3
Ozone
Molecule
Allotropes of Carbon
Diamond
Graphite
All are pure carbon. Each has a different structure.
Fullerenes
Carbon Nanotubes
COMPOUNDS
 Are pure substances that are
composed of multiple types of
elements (2 or more),
chemically bonded to one
another.
 Compounds can not be
broken down by physical
methods (they can be broken
down by chemical reactions).
COMPOUNDS
 Have definite compositions,
with element ratios indicated by
subscripts (H2O).
 We call this building block
the “water molecule”.
COMPOUNDS
 The properties of compounds
are very different from the
properties of the elements that
make them up!
Na + Cl  NaCl
MIXTURES
A mixture is something that CAN be broken
down into simpler materials using
physical methods.
There are 3 possible types of mixtures:
1) Element + Another Element
2) Compound + Another Compound
3) Element + Compound
MIXTURES
There are 2 main types of mixtures:
a) Homogeneous- The parts are distributed
evenly.
Examples: Salt water; syrup; air; brass.
MIXTURES
Homogeneous mixtures of liquids are called
solutions.
Homogeneous mixtures of metallic atoms
are called alloys.
b) Heterogeneous- The parts are distributed
unevenly.
Examples: Spaghetti and Meatballs;
Water + Oil mixture.
We learned that the properties of
compounds are TOTALLY DIFFERENT
from the properties of the elements that
make them up.
In contrast, the properties of mixtures ARE
related to the properties of the substances
that make the mixtures up.
Properties of
Saltwater
Matter Flowchart
MATTER
yes
MIXTURE
yes
Is the composition
uniform?
Homogeneous
Mixture
Solutions +
Alloys
no
Can it be physically
separated?
PURE SUBSTANCE
no
Heterogeneous
Mixture
yes
Can it be chemically
decomposed?
Compound
no
Element
What are each
of these?
Atom,
Element,
Molecule,
or
Compound
Four different molecules:
• Which are compounds?
Warmup 11/21/11 (R)
Types of Particles: Atoms or Molecules or Both?
Types of Matter: Elements or Compounds or Mixture?
Chemical Symbols Represent
Elements Chemical
Symbols are
either one or two
letters.
If one letter, it is
always
capitalized.
A chemical symbol implies one
atom of that element.
If two letters, the
first is
capitalized, the
second is lower
case.
Chemical Formulas show how many
atoms of each element are in one molecule
of an element or compound:
Chemical
Formula
# of
elements
# of atoms # of Carbon
total
atoms
O2
1
2
0
H2O
2
3
0
C3H8O
3
12
3
C6H12O4Cl
4
23
6
Nuts, Bolts, Washers
Is it an element, compound, or mixture?
What are the element and compound formulas?
Nuts, Bolts, Washers
Is it an element, compound, or mixture?
What are the element and compound formulas?
Nuts, Bolts, Washers
Is it an element, compound, or mixture?
What are the element and compound formulas?
WRITING FORMULAS
When writing formulas, list the elements in
this order:
First…bolts. (Bo)
Second…nuts. (Nu)
Third…washers. (Wa)
Example: BoNuWa2
• All pure substances can be represented
by a
Single Chemical Formula:
H2O
If it’s really a pure substance, you should only need to
write ONE chemical formula to describe it’s composition.
How many atoms of each
element are present in one
molecule of:
(NH4)2SO3
N…………….
H……………
S…………….
O……………
2
8
1
3
Practice with Vocabulary:
Methods of Mixture Separation
1) Mechanical Separation (often by hand)
takes advantage of physical properties
such as color and shape.
Example: Recycling Plastic, Paper, Metal
Methods of Mixture Separation
2) Magnetic Separation takes advantage of
the physical property of magnetism.
Example:
Separating Metals in
a Scrap Yard
Methods of Mixture Separation
3) Filtration takes
advantage of
the physical
property of the
state of
matter. A
screen lets the
liquid particles
through, but
traps the solid
particles.
Example: Filtering Coffee, Spaghetti
A filter can
also be used
to separate
solid
particles of
different
sizes.
(ex. a window
screen, an air
filter, a sand
sieve)
Methods of Mixture Separation
4) Decanting:
To pour off a
liquid, leaving
another liquid
or solid behind.
Takes
advantage of
differences in
density.
Example: To decant a liquid from a precipitate
or water from rice.
Methods of Mixture Separation
5 ) Distillation:
The
separation of
a mixture of
liquids based
on the
physical
property of
boiling
point.
Example: the distillation of alcohol or oil
A distillation tower or “still”
Methods of Mixture Separation
6) Evaporation:
Vaporizing a
liquid and
leaving the
dissolved
solid(s)
behind.
Used to
separate salt
solutions.
Example: Obtaining sea salt from sea water
Methods of Mixture Separation
Density Separation:
More dense components
sink to the bottom and
less dense components
float.
Methods of Mixture Separation
7) Centrifuge:
Circular
motion helps
denser
components
sink to the
bottom faster.
Examples: The separation of blood or DNA from blood
Methods of Mixture Separation
8)
Paper
chromatography:
Uses the property of
molecular attraction to
separate a mixture.
Different molecules
have different
attractions for the paper
(the stationary phase)
vs. the solvent (the
mobile phase)
Example: the separation of
plant pigments and dyes
Methods of Mixture Separation
Fractional
Crystallization:
Dissolved
substances
crystallize out of a
solution once their
solubility limit is
reached as
the solution cools.
Examples: Growing Rock Candy or the Crystallization of a
Magma Chamber