Elements, Compounds, and
Mixtures
3 KINDS OF MATTER
Elements
Compounds
Mixtures
Elements
All (living and nonliving) of the different
kinds of matter in the universe is made
from about 100 different substances,
called elements.
Elements are called the building blocks of
matter because all matter is composed of
elements.
Each element is made up of the same type
of atoms.
Compounds
 A compound is a substance made of two or
more different kinds of elements chemically
combined in a specific ratio.
 Each compound is represented by a formula that
uses symbols to identify which elements are
present.
 A formula shows the ratio of elements in the
compound.
 H2O – ratio of Hydrogen is 2:1 Oxygen
The symbols make up the formula. A
formula is just chemical shorthand for the
compound.
 The subscript lets us know how many
atoms are present.

The coefficient lets us know how many
molecules are present.
Compounds
Molecules
A molecule is formed when two or more
atoms join together chemically.
Diatomic molecules are made of two
atoms of the same element.
Hydrogen – H2
Oxygen – O2
What is the difference between a
compound and a molecule?
A molecule is formed when two or more
atoms join together chemically.
A compound is a molecule that contains at
least two different elements.
All compounds are molecules but not all
molecules are compounds.
Molecular hydrogen (H2), molecular
oxygen (O2) and molecular nitrogen (N2)
are not compounds because each is
composed of a single element.
Water (H2O), carbon dioxide (CO2) and
methane (CH4) are compounds because
each is made from more than one
element.
Molecule
The smallest bit of each of these
substances would be referred to as a
molecule. For example, a single molecule
of molecular hydrogen is made from two
atoms of hydrogen.
A single molecule of water is made from
two atoms of hydrogen and one atom of
oxygen.
Mixtures
 Most matter in the
universe is found in
mixtures.
 A mixture is made
from two or more
substances either
elements, compounds
or both - that are not
chemically combined.
Mixtures and
compounds differ
in two ways…
Substances in a mixture keep
their individual properties.
Parts of a mixture are not
necessarily present in specific
ratios.
Compound
A compound has properties different than
the elements that make it up.
The parts of a compound are present in
specific ratio’s.
Compounds and Mixtures
Most of the matter around you is in the
form of compounds or mixtures.
Water, carbon dioxide, salt, vinegar,
baking soda, lye, sugar, gasoline, and
bleach are all chemical compounds.
Heterogeneous Mixture
A mixture in which different materials can
be easily distinguished.
Pizza, dry soup, chex mix, trail mix are all
examples.
Solutions
Homogeneous mixture: is a substance in
which two or more substances are
uniformly spread out. For example salt
water.
Solution is another term for homogeneous
mixture.
Solutions
Solute is the substance being dissolved.
Solvent is the substance that dissolves a
solute.
Solubility is the amount of a substance
(solute) that will dissolve in a solvent.
Example
Salt water:
The water is the solvent
NaCl is the solute
Colloids and Suspensions
A colloid is a heterogeneous mixture that
like a solution never settles. Milk and
smoke are examples.
One way to tell a colloid from a solution is
because milk is appears white because its
particles scatter light. Called the Tyndall
Effect.
suspension
A suspension is a heterogeneous mixture
containing a liquid in which visible particles
settle.
River water
NaCl is the formula for salt
Water is H2O
An oxygen atom can bond
with two hydrogen atoms to
make a molecule we call
water. Water is an example of
a compound, because it
contains more than one kind
of atom. The formula for
water is H2O, meaning there
are two hydrogen atoms for
each oxygen atom.
Carbon Dioxide CO2
Carbon dioxide molecules are made from
one carbon and two oxygen atoms joined
together by covalent bonds. The chemical
symbol is CO2.
Glucose - C6H12O6
Molecule
 When a compound is broken down into its’
smallest piece it is called a molecule. You should
be able to write the formula for the following:
 Water
 Oxygen
 Carbon Dioxide
DNA
Is a large molecule made up of carbon,
hydrogen, nitrogen, oxygen, and
phosphorous.
Kinetic theory of matter
The idea that all matter is made up of
constantly moving tiny particles.
Elements form compounds to try to fill their
outer energy level with valence electrons.
 This is called chemically stable. If the
atom is not chemically stable it will lose,
share, or gain electrons.
 A chemical bond is the force that holds
together the atoms in a substance.
Ion


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An Ion is an atom or group of atoms
that has become electrically charged.
A When an atom loses an electron it
loses a negative charge and becomes a
positive ion.
When an atom gains an electron, it
gains a negative charge and becomes a
negative ion.
Forming an Ionic Bond:
. Sodium has one valence electron and
transfers that electron to chlorine
Na + Cl- the negative and positive
electrical charges attract each other so the
oppositely charged ions come together
and form sodium chloride (salt).
 An ionic bond is the attraction
between two oppositely charged ions.
This attraction is similar to the attraction
between opposite poles of two magnets.
 .
When two ions come together the
opposite charges cancel out.
Compounds are electrically neutral. When
the ions come together they do so in a
way that balances out the charges on the
ions
Molecules and Covalent Bonds

The attraction that forms between
atoms when they share electrons is
known as a covalent bond.