Bonds and Compounds
How to write, name and/or
draw various Chemical
Compounds
Ions and Ionic
Compounds
• An ion is created whenever an atom
gains or loses an electron to become
more stable like a Noble Gas, meaning
that its valence number is now 8!
• Metals are always positive, which
means that they lose electrons.
• Nonmetals are usually negative with a
few exceptions, like Nitrogen which
has 8 different ion possibilities.
How to make an ionic
compound
• To make an ionic compound, one must
combine a positive ion with a negative ion.
• The positive ion is ALWAYS listed first,
followed by the negative one.
• Example: Na+ + Cl-  NaCl
• **The Key is that ALL charges must be
cancelled out, and the overall charge on the
compound MUST be ZERO!!
Criss-Cross Method
• When the ratio is one-to-one or two-totwo, it is easy to cancel the charges.
However, it can become a little more
complicated, so scientists use the
Criss-Cross Method to help illustrate
how the math is done.
• Example:
• Fe3+ + SO42- = Fe2(SO4)3
Naming Ionic
Compounds
• The first part of the name comes directly
from the first ion in the compound.
• The second part of the name has the base
of the second ion, but MUST end in –ide, ate, or –ite.
• Examples:
NaCl
Sodium Chloride
K2CrO4
Potassium Chromate
Al2(SO3)3 Aluminum Sulfite
Writing the formula from
the name
• Unfortunately, there is no shortcut to
this. You MUST learn the ion to know
what their charges are to write the
formula from the names. It takes
practice and perseverance.
• Examples:
• Calcium Carbonate CaCO3
• Ammonium Phosphate (NH4)3PO4
Review and Practice
• Name the following ionic
compounds:
(NH4)3PO4
CaSO4
• Write the formulas for the
following ionic compounds:
Tin (IV) Fluoride
Iron (III) peroxide
More Practice
• Write the formulas for the following ionic
compounds:
Magnesium Hydroxide
Copper (I) Sulfate
Lead (II) Phosphate
Ammonium Dichromate
Zinc Acetate
Iron (II) Oxide
Mercury (I) Chloride
Silver Nitrate
Covalent or Molecular
Compounds
• Covalent compounds are created
using covalent bonds. A covalent
bond involves the “sharing’ of
electrons between two different
atoms. These atoms can be the same
type of atoms or different.
• To show the sharing of electrons,
scientists use Lewis Dot Structures
and structural formulas that use
dashes for bonds.
Naming Covalent
Compounds Number
1
• To name covalent
2
compounds, one
3
must know ten
important prefixes. 4
These prefixes
5
indicate how many
6
of each atom is
present in the
7
molecule that has
8
been created.
9
10
Prefix
MonoDiTriTetraPentaHexaHeptaOctaNonaDeca-
Naming them…
• First, you must see if the two atoms are
nonmetals. If so, then you have a covalent
compound. (Be careful not to mistake an
ion for an atom!)
• Second, note how many of each atom is
present in the compound.
• Third, choose the prefix that will work for
the name. (The first atom only gets a prefix
if there is more than one; the second atom
ALWAYS gets a prefix.)
• Fourth, name it using the prefixes as
needed. (Be careful…some compounds
have common names that are the preferred
names.
Examples…
• CO2
Carbon dioxide
• H2O Dihydrogen monoxide
(Water)
• NH3 Nitrogen trihydride
(Ammonia)
• P4O10 Tetraphosphorus decoxide
Types of Chemical
Reactions
• There are five major types of
reactions.
• These reactions are found in nature
and can be manmade.
• In addition, these reactions often take
in heat or energy (endothermic) or
release heat or energy (exothermic).
Synthesis Reactions
• These reactions have two or
more reactants that come
together to form ONE product.
• Generic equation:
A + B  AB
• Example:
2H2 + O2  2H2O
Decomposition Reactions
• These reactions involve ONE reactant
breaking down to form two or more
products.
• Generic Equation:
AB  A + B
• Example:
RhO3  RhO + O2
Single-Replacement
Reactions
• These reactions require a single atom
combined with a compound to then
form a new compound and a new
singular atom. (**Governed by the
Activity Series of Metals)
• Generic Equation:
A + BC  AC + B
• Example:
2Li + H2SO4  Li2SO4 + H2
Double-Replacement
Reactions
• These reactions involved two ionic
compounds’ cations switching anion
partners to form new compounds.
(**A gas or precipitate usually forms!)
• Generic Equation:
A+ B- + C + D-  A + D- + C+ B• Example:
AgBr + NaCl  AgCl + NaBr
Combustion Reactions
• All combustion reactions involve
oxygen gas as a reactant and the
release of great amounts of energy as
a product. There are types of
combustion reactions: Metals with
oxygen to form metal oxides and
hydrocarbons with oxygen to form
carbon dioxide and water.
Combustion Reactions
(cont.)
• Examples of both combustion
reactions:
2Mg + O2  2MgO + light
C2H4 + 3O2  2CO2 + 2H2O + energy