Types of Bonding Lab
Wrap Up
What Do The Formulas Mean?
Describe what elements make up the
compound
 Also describes how many of each type of
atom there are in the compound

What
Elements
Are
Present
C2H2F4
How many
of each
there are
More Complicated Formulae

Formulae may have the same element
more than once. This indicates something
about the chemical structure, which we will
learn about in Unit 5.

For example: NH4OH
More Complicated Formulae

Formulae may have parentheses:
For example: Al(NO3)3
 The number outside the parentheses applies
to each of the atoms in the parentheses
How Many of Each Atom
Are In A Formula?
C3H8O
MgSO4
Ca(OH)2
NH4NO3
Mg3(PO4)2
Fe(NO3)3
What Does Conductivity Mean?
How well a solution conducts electricity
 What do you need to conduct electricity?


To conduct electricity you need moving
charges

Things with high conductivities have lots of
things with charges that can move.
A Few Conductivity Terms

Electrolyte – a compound that conducts
electricity when dissolved in water.
Strong electrolyte – conducts electricity
well
 Weak electrolyte – conducts electricity
slightly
 Non-electrolyte – does not conduct
electricity

What does the Melting Point mean?

When a compound
changes states some
of the forces that
attract the various
pieces together are
broken.

Low melting points
indicate weak
attractions between
the little bits.
What Does Appearance Mean?

Regular Shapes are very important in
science

A Regular Shape at the visible level
means that there is a very Regular Shape
at the microscopic and atomic levels.
Types of Chemical Bonding
What Makes Salt, Aspirin, and
Zinc Have Such Different
Properties?
Things Like Sodium Chloride





High Melting Points
Do Not Conduct
Electricity in Solid
Form
Conduct Electricity in
Solution
Have a regular shape
Made from a metal
and a nonmetal (ex.
NaCl)
Things Like Sodium Chloride





Metal loses electrons
while nonmetal gains
electrons (Na+ and Cl-)
Make ions = charged
things
Opposite Charges Attract
Have a regular crystal
structure
Crystals come from a
repeating pattern of ions.
Things Like Sodium Chloride


Pattern of ions repeats
billions of times in a single
crystal = CRYSTAL
LATTICE
Has no specific number of
atoms in crystal so we use
an empirical formula


Empirical formula - Lowest
whole number ratio of
atoms
Call these compounds
“salts”
Things Like Sodium Chloride


When melted, ions are
freed from the crystal
lattice structure
Melting requires breaking
the bonds holding the
compound together


Bonds are strong
Therefore, melting point is
high.
IONIC BONDING
Bonding between ions
Atoms give and take electrons
Transfer electrons
Things like Salt
Things Like Aspirin





Low Melting Points
Do Not Conduct
Electricity in Solid Form
Most Do Not conduct
electricity in aqueous
solution (some
compounds in this
category do a little bit)
Have an irregular shape
Made from all
nonmetals (ex. C9H8O4)
Things Like Aspirin


Atoms share pairs of
electrons between
each other (potluck
dinner)
Shared electrons hold
the atoms together
Things Like Aspirin


Smallest units have a
distinct beginning and
a distinct end =
MOLECULE
Has a specific
number of atoms in
the molecule (ex.
C9H8O4)
Things Like Aspirin

One line = SINGLE
BOND = 2 electrons

Two lines = DOUBLE
BOND = 4 electrons

Three lines = TRIPLE
BOND = 6 electrons
Things Like Aspirin


When melted, bonds
between atoms do
NOT break
Instead, attractive
forces between
molecules break.


Intermolecular Forces
Intermolecular forces
are weak compared
to bonds.

Melting point is low.
COVALENT BONDING
Atoms Share Electrons to Make
a Compound
Things like Aspirin
Things Like Zinc





High Melting Points
DO conduct electricity
in the solid state
Don’t form aqueous
solutions
Have irregular shape
but are malleable
Made from all metals
(ex. Brass – a mixture
of copper and zinc)
Things Like Zinc





Overlap of the outer
orbitals of the metal
atoms
Creates metal ions
Electrons move freely
through the whole
piece of metal
Sea of Electron Glue
“Delocalized”
electrons
Things Like Zinc

When metals melt,
some of the
attractions from the
sea of electrons are
broken.

Bonds are broken.

Melting point is high.
Things Like Zinc
Because of the sea of
electrons metals:
 Can have its shape
changed =
MALLEABLE
 Can be pulled into
wire = DUCTILE
 Are shiny =
LUSTEROUS
METALLIC BONDING
A Sea of Electron Glue Holds
Atoms Together
Delocalized Electrons
Things like Zinc