The
Classification of
Matter:
Atoms, Elements,
Molecules and
Compounds
Chemistry:
The study of matter and its
changes
Matter:
Anything that has mass and
volume
Atom:
The basic unit of matter
Element:
A type of atom
Each element has a name and symbol:
Not all elements are equally
common
Kinetic Molecular
Theory
Matter is made of tiny
particles called atoms, which
combine to form molecules.
Molecule:
A group of atoms held together by
sharing electrons (covalent bonds)
Compound:
A substance containing more than one
element.
Examples:
• Atom, Element, Molecule, Compound:
Four different molecules:
• Which are compounds?
Some molecules are more complex:
Some fat molecules:
A protein
molecule:
cholester
What are each
of these?
Atom,
Element,
Molecule,
or
Compound
Allotropes
• One of several different forms of an
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
molecular or crystalline form.
Fullerenes
Carbon
Practice with Vocabulary:
Molecules can be represented many ways:
Chemical
Formula:
CH4
H2O
H
Structural Formula:
Ball and Stick
Model:
Space Filling Model:
H
O
• All molecules can be represented by a
Chemical Formula:
H2O
subscript
Chemical Formulas show how many atoms
of each element are in one molecule:
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
How many atoms of each
element are present in one
molecule of:
(NH4)2SO3
N…………….
H……………
S…………….
O……………
2
8
1
3
The
Classification
of Matter:
Pure Substances
and Mixtures
Pure Substance:
= An element or a compound
(Any substance
that can be described
by a single chemical formula)
Mixture:
A substance that contains
more than one pure substance
Pure Substance or Mixture?
Pure Substances:
• Are made of only one compound or one
element.
• Can be represented by one chemical
Examples:
formula.
Salt
NaCl
Copper
Cu
Water
H2O
Mixture:
Anything that contains more than one pure
substance.
Examples:
Juice, Granite, Salad Dressing, etc…
Homogenous Mixture
An even mixture; particles are blended
evenly throughout the mixture.
(= “solutions”)
Heterogeneous Mixture:
An uneven mixture;
particles are unevenly distributed.
A. Matter Flowchart
MATTER
yes
MIXTURE
yes
Is the composition
uniform?
Homogeneous
Mixture
(solution)
PURE SUBSTANCE
no
Heterogeneous
Mixture
Colloids
no
Can it be physically
separated?
yes
Can it be chemically
decomposed?
Compound
Suspensions
no
Element
Pure Substance:
A substance that contains
only one type of atom or molecule
Mixture:
A substance that contains
more than one pure substance
• 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.
Distillation
Vacuum Filtration
Electrolysis