Naming Compounds
Use handout for notes.
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Covalent – show sharing of e-
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Ionic – show transfer of e-
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Ionic – show transfer of e-
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These have only 2 elements and are ionic (1
metal and 1 nonmetal).
Write the name of the cation (metal).
Then write the name of the anion (nonmetal)
but end it with the suffix –ide.
Examples:
sodium chloride (NaCl)
Calcium oxide (CaO)
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Anion nonmetals form ions with negative
charges.
Group number – 8 = charge
Examples:
nitrogen: 5-8=-3
Oxygen: 6-8=-2
Iodine: 7-8=-1
Element
Ion Name
Ion Symbol
Ion Charge
Fluorine
Fluoride
F-
-1
Chlorine
Chloride
Cl-
-1
Bromine
Bromide
Br-
-1
Iodine
Iodide
I-
-1
Oxygen
Oxide
O2-
-2
Sulfur
Sulfide
S2-
-2
Nitrogen
Nitride
N3-
-3
Phosphorus
Phosphide
P3-
-3
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The alkali metals (group 1A), alkaline earth
metals (group 2A), and aluminum form ions
with a positive charge equal to their number
of valence electrons (or group number).
Examples:
Element
Ion symbol
Charge
Potassium
K+
+1
Calcium
Ca2+
+2
Aluminum
Al3+
+3
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The transition metals form cations differently.
They form more than 1 type of ion.
Use a Roman numeral next to the ion name to
indicate its charge.
Examples: copper can be copper (I) with a +1
charge or copper (II) with a +2 charge
Element
Ion Name
Ion Symbol
Copper
Copper (I)
Cu+
Copper
Copper (II)
Cu2+
Iron
Iron (II)
Fe2+
Iron
Iron (III)
Fe3+
Lead
Lead (II)
Pb2+
Lead
Lead (IV)
Pb4+
Chromium
Chromium (II)
Cr2+
Chromium
Chromium (III)
Cr3+
Titanium
Titanium (II)
Ti2+
Titanium
Titanium (III)
Ti3+
Titanium
Titanium (IV)
Ti4+
Mercury
Mercury (II)
Hg2+
Common Ion Charges
1+
0
2+
3+ NA 3- 2- 1-
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The total (net) charge of an ionic compound
must be 0 (zero).
The cation and anion charges must cancel
each other out.
Example:
Copper (II) oxide– copper has a charge of +2
and oxygen has a charge of -2
+2 cancels -2 to equal 0
1.
2.
3.
4.
5.
Titanium (II) sulfide
Copper (I) oxide
Lead (II) oxide
Lead (IV) nitride
Mercury (II) iodide
1.
2.
3.
4.
5.
**Titanium (II) sulfide +2-2=0
Copper (I) oxide +1-2=-1
**Lead (II) oxide +2-2=0
Lead (IV) nitride +4-3=+1
Mercury (II) iodide +2-1=+1
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Copper (1) oxide
CuO
Does not balance to 0
+1-2=-1
But 2 atoms of copper (1) would make it
equal 0
Cu20
+1+1-2=0
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Mercury (II) iodide +2-1=+1
HgI
Does not balance to 0, but…
HgI2
+2-1-1=0
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Lead (IV) nitride +4-3=+1
PbN
Does not balance to 0, but…
Pb3N4
+4+4+4-3-3-3-3=0
+12-12=0
1.
2.
3.
4.
5.
Iron (II) bromide
Chromium (III) nitride
Lead (IV) oxide
Titanium (III) fluoride
Lead (IV) phosphide
1.
2.
3.
4.
5.
Iron (II) bromide
Chromium (III) nitride
Lead (IV) oxide
Titanium (III) fluoride
Lead (IV) phosphide
FeBr2
CrN
PbO2
TiF3
Pb3P4
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The atoms in polyatomic ions are joined by
covalent bonds but have a net + or – charge.
The prefix poly- means many.
Polyatomic ions contain many ions.
Example:
Ammonium contains 1 nitrogen and 4
hydrogen atoms.
-3+1+1+1+1=-3+4=+1 (net charge)
Ion Name
Formula
Ion Name
Formula
Ammonium
NH4+
Acetate
C2H3O2-
Hydroxide
OH-
Peroxide
O22-
Nitrate
NO3-
Permanganate
MnO4-
Sulfate
SO42-
Hydrogen sulfate
HSO4-
Carbonate
CO32-
Hydrogen
carbonate
HCO3-
Phosphate
PO43-
Hydrogen
phosphate
HPO42-
Chromate
CrO42-
Dichromate
Cr2O72-
Silicate
SiO32-
Hypochlorite
OCl-
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I will give you polyatomic ion formulas on the
test.
There is a chart in your book on page 173 to
use on classwork and homework.
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Polyatomic ions can combine with metals to
form compounds.
Put the polyatomic ion in parentheses when
you write the formula.
Example:
Iron (III) hydroxide
Fe(OH)3
Iron has a +3 charge and hydroxide has a -1
charge. You must have 3 hydroxide ions to
balance the iron and make the net charge 0.
1.
2.
3.
4.
5.
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Chromium (II) sulfate
Lead (IV) hydroxide
Mercury (II) acetate
Copper (I) sulfate
Titanium (IV) dichromate
See page 173 for the polyatomic ion
formulas.
1.
2.
3.
4.
5.
Chromium (II) sulfate
Lead (IV) hydroxide
Mercury (II) acetate
Copper (I) sulfate
Titanium (IV) dichromate
Cr(SO4)
Pb(OH)4
Hg(C2H3O2)2
Cu2(SO4)
Ti(Cr2O7)2
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Consider the following:
◦ Does it contain a polyatomic ion?
 -ide, 2 elements  no
 -ate, -ite, 3+ elements  yes
◦ Does it contain a Roman numeral?
 Check the table for metals not in Groups 1 or 2.
◦ No prefixes!
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These are called molecules.
Name the most metallic element (the one that
appears the furthest left on the periodic
table) first.
If both elements are in the same group, name
the one closest to the bottom first.
Add the suffix –ide to the second element.
Example: carbon dioxide
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Use the Greek prefixes to indicate how many
of each atom are in the molecule.
Number
Prefix
Number
Prefix
1
Mono-
6
Hexa-
2
Di-
7
Hepta-
3
Tri-
8
Octa-
4
Tetra-
9
Nona-
5
Penta-
10
Deca-
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N2O4
Dinitrogen tetraoxide
Di = 2 nitrogens
Tetra = 4 oxygens
Because nitrogen is a group left of oxygen
name it first
Because oxygen is named second, change it
to end in -ide
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NO2
Mononitrogen dioxide
If there is only 1 of the first element, it is not
necessary to use the mono- prefix.
Nitrogen dioxide
1.
2.
3.
4.
5.
NO2
P2F4
P2O5
CO
N2S5
1.
2.
3.
4.
5.
NO2
P2F4
P2O5
CO
N2S5
nitrogen dioxide
diphosphorus tetrafluoride
diphosphorus pentaoxide
carbon monooxide
dinitrogen pentasulfide
1.
2.
3.
4.
5.
Nitrogen dioxide
Diphosphorus tetrafluoride
Carbon dioxide
Dihydrogen oxide
Dinitrogen tetraoxide
1.
2.
3.
4.
5.
Nitrogen dioxide
Diphosphorus tetrafluoride
Carbon dioxide
Dihydrogen oxide
Dinitrogen tetraoxide
NO2
P2F4
CO2
H2O
N2O4
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The Seven Diatomic Elements
Br2 I2 N2 Cl2 H2 O2 F2
H
N O F
Cl
Br
I