ionic compound
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Transcript ionic compound
Ion: A Charged Atom
By gaining or losing electrons, atoms become
ions.
ANIONS: Atoms that have gained
electrons and have a negative charge
-Nonmetals form anions
CA+IONS: Atoms that have lost electrons
and have a positive charge
-Metals form cations
OXIDATION NUMBERS ARE PERIODIC
Group
#
Oxid. #
1
2
13
14
15
16
17
18
Monatomic Ions: 1 Atom Ions
• To Name:
– Positive Monatomic Ions: Name the metal, if
it is a transition metal, add a Roman Numeral
to indicate the number of the charge
– Negative Monatomic Ions: Change the
ending of the elements name to –ide
Example--Name the following:
Cu+1
Ca+2
Cl-
Polyatomic Ions: More than 1 atom ions
Polyatomic Ions end in –ate or –ite and are
found in the chart at the bottom of your periodic
table…just look them up
Examples: Name the following
CO32OHWrite the formulas of the following:
Nitrite
Perchlorate
What do opposites do? ATTRACT
A metal will lose electrons to become stable. What charge
will that metal have after it loses electrons? + (Metals form positive ions)
A nonmetal will gain electrons to become stable. What
charge will that nonmetal metal have after it gains electrons?
- (Nonmetals form negative ions)
If metal ions are in a container with nonmetal ions…What will happen?
ATTRACT—Come together in an ionic bond
Ionic Bond
• The strong attractive force between ions of
opposite charge. Occurs when one atom
transfers electrons to another atom to become
stable
• Electrons are transferred in an ionic bond.
• Ionic bonds form between metals and nonmetals
EMPIRICAL FORMULA
• Chemical formula for an ionic compound
• Lowest whole number ratio of ions in an
ionic compound
EMPIRICAL FORMULA
Al2O3
Subscript: # written to the lower right of a
chemical symbol that shows the number of
atoms of that element present in the
compound
1
Using oxidation numbers to determine the empirical formula
of a compound.
Because compounds are all
_____________ in charge, the total sum
of the oxidation numbers in a compound
must be ________.
Determine the number of each ion
necessary so that the sum of the charges
is 0.
Using the crisscross method to determine the empirical
formula of an ionic compound.
2
Write the symbol of charge of each ion in the
compound
Crisscross each ions numerical charge down to
the subscript of the other ion
Can check your answer—the charges will still add up to be 0
Sr+2
N3-
Sr3N2
Naming Ionic Compounds
Make sure it is an ionic compound. How can you tell?
It contains a metal & nonmetal(s) or ammonium & nonmetal(s).
Determine if it’s a binary or a ternary ionic compound.
Binary = 2 elements
Ternary = More than 2 elements
Ternary compounds contain a
Polyatomic ion
____________________
2
Ionic compounds will have only _________words
in their
names. This is because all ionic compounds are composed
cation
of just 1 ____________
and just 1 ______________.
anion
If the compound has more than 2 elements than one of
the ions is a ______________________________
ion.
Polyatomic ion
Naming a Binary Ionic Compound
To Name an Ionic Compound
Name the metal
If the metal is a transition
metal, add a Roman numeral in
parentheses to indicate it’s
charge
Name the nonmetal,
changing its suffix to –ide
CaCl2
Fe2O3
Na2O
EXAMPLES
To Name an Ionic Compound
Name the metal
If the metal is a transition
metal, add a Roman numeral in
parentheses to indicate it’s
charge
Name the nonmetal,
changing its suffix to -ide
CuCl
MnO
AlBr3
Naming a Ternary Ionic Compound
To Name an Ternary Ionic
Compound
Does the formula begin with
NH4? If so the first word is
ammonium. If not, name
the metal
If the metal is a transition
metal, add a Roman numeral in
parentheses to indicate it’s
charge
Name the polyatomic ion.
CaSO4
Cu(C2H3O2)2
NH4OH
Naming a Ternary Ionic Compound
To Name an Ternary Ionic
Compound
Does the formula begin with
NH4? If so the first word is
ammonium. If not, name
the metal
If the metal is a transition
metal, add a Roman numeral in
parentheses to indicate it’s
charge
Name the polyatomic ion.
Al(ClO)3
KSCN
NaHCO3
Examples
Name the following ionic compounds.
LiCl
Ca(OH)2
(NH4)2S
KI
CoO
Ni(NO3)2
IONIC VS. COVALENT BONDING
IONIC
www.blobs.org/science/article.php?article=17Remove frame
COVALENT
Molecular Compounds
Molecular compounds form when elements
share
__________________
electrons to form
compounds.
Also known as covalent compounds.
How can you distinguish a molecular
compound from an ionic compound based on
its chemical formula or chemical name?
Ionic Compounds are made of metals combined
with nonmetals. Molecular compounds are
made of all nonmetals!
Which type of bond would form between the
following elements?
MgCl2
CI4
AlN
CO2
OF2
SnO2
Molecule
A group of atoms united by covalent
bonds
Polyatomic Ions are molecules that have
charge!
DIATOMIC MOLECULES:
Some elements only exist in nature as molecules consisting of 2
atoms of that element.
•Why? More stable as a pair!
•The 7 diatomic elements are: HONClBrIF
Molecular Substance
Substance made of molecules
Molecular Formula
Tells how many atoms of an element are in a single molecule of a
compound
The chemical formula of a covalent compound is not the lowest
whole number ratio
Different from an EMPIRICAL FORMULA which gives the lowest
whole number ratio of ions in an IONIC COMPOUND
To Name a Molecular Compound
Name the 1st element. If there is more
than one of that element, use the
appropriate prefix (mono- is not used on
the first element)
Name the last element using the
appropriate prefix and changing its ending
to –ide.
Since there are no metals in molecular
compounds, no Roman numerals are used.
NUMERICAL PREFIXES
1
Mono-
2
Di-
3
Tri-
4
Tetra-
5
Penta-
6
Hexa-
7
Hepta-
8
Octa-
9
Nona-
10
Deca-
Examples
N2O4
PCl5
NO2
Dinitrogen tetroxide
Phosphorous pentachloride
Nitrogen dioxide
Chemical Formulas for Molecular
Compounds
Use the prefixes to determine the
chemical formula
Since molecular compounds do not involve the
transfer of electrons, there are no ions—do not
get charges and no crisscrossing!
Examples
Nitrogen trifluoride
NF3
Diphosphorus pentoxide
P2O5
Carbon tetrachloride
CCl4
HYDRATES
An ionic compound that
contains water within its
crystal structure
Anhydrous: A compound in
which all water has been
removed.
The water may be evaporated
off of a hydrate to leave the
anhydrous form of the
substance
HYDRATES
To Identify a hydrate
BaCl2 3H2O
barium chloride trihydrate
To Name a hydrate
Name the ionic compound followed by the word hydrate with
a prefix to indicate the # of water molecules attached.
MgSO4 2H2O
To Write the Formula for a Hydrate
Use the crisscross method to determine the formula of the
ionic compound, followed by a dot, followed by the # of water
molecules indicated by the prefix.
Copper(II) chloride pentahydrate
Acids
A molecular substance that
dissolves in water to produce H+
ions
The chemical formula starts with H
(we will assume all are dissolved in
water)
To Name a Binary Acid
“Hydro”-root name of anion-“ic Acid”
Ex: Hydrobromic Acid
To Name an Acid containing a
Polyatomic Ion
Root name of Polyatomic Ion- “ic” Acid
Ex: Sulfuric Acid
To determine the formula of an acid
Consider Hydrogen an Ion: H+
Determine the charge of the anion
Crisscross charges
H+ S2-
H2S