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 List differences among ionic and covalently bonded compounds
 Identify polyatomic and monatomic ions and name them properly
 Write the chemical formulas and names for ionic compounds
 Write the chemical names and formulas of acids
 Write the chemical names and formulas of molecules
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Review of Ionic Compounds (Crystals)
 Transfer of electrons
 Made from a metal and a non-metal
 Metals lose electrons, nonmetals gain electrons
 Chemical formula is arranged in the smallest whole number ratio (empirical formula)
 Formula unit: the smallest repeating pattern within a crystal
 Even though ionic compounds are made up of ions, they ARE ELECTRICALLY
NEUTRAL!
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Ions can be monatomic or polyatomic:
 Monatomic:
Made up of a single atom
 Polyatomic:
Made up of multiple atoms
Remember…
Group #: 1 2 13 14 15 16 17 18
Charge: +1 +2 +3 X -3 -2 -1 X
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 Monatomic cations have the same name as the element
 Example: Na +1 = Sodium ion, Ca +2 =
Calcium ion
 Monatomic anions have the ending of the element name changed to“-ide”
 Example: Cl -1 =chloride ion, O -2 =oxide ion
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Polyatomic ions:
(See polyatomic ion sheet) are made up of two or more elements covalently bonded together with an overall positive or negative charge.
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Review Molecular Compounds (Molecules)
 Sharing of electrons
 Made from nonmetals only
 Molecules of the same compound are
IDENTICAL and INDEPENDENT of each other
 Chemical formula indicates the exact makeup of one molecule (molecular formula)
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Since all compounds are neutral, figure out how many of each ion is needed to make a neutral compound.
(Neutral means having a net zero charge.)
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Mg and Cl
Mg +2 Cl -1
Cl -1
MgCl
2
Al and O
Al +3 O -2
Al +3 O -2
O -2
Al
2
O
3
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Ca and S
Ca +2 S -2
CaS
Ca and (AsO
4
)
Ca +2 (AsO
4
) -3
Ca +2 (AsO
4
) -3
Ca +2
Ca
3
(AsO
4
)
2
Parentheses are needed if there is more than one of the polyatomic ions!
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Aluminum Sulfite
Al +3 (SO
3
) -2
Al +3 (SO
3
) -2
(SO
3
) -2
Al
2
(SO
3
)
3
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Silver Sulfate
Ag ?
+1 (SO
4
) -2
Ag +1
Ag
2
(SO
4
)
Use your Periodic Table to determine the charge on transition metals!
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Nickel (II) Nitrate
Ni +2 (NO
3
) -1
(NO
3
) -1
Ni(NO
3
)
2
The Roman Numeral will always tell you the charge and it will always be positive
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Iron (III) Chloride
Fe +3 Cl -1
Cl -1
Cl -1
FeCl
3
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Recall the format for chemical formulas…
(name of cation – metal) (name of anion – nonmetal)
Examples:
KBr Potassium Bromide
CaI
2
Na(SO
4
)
Calcium Iodide
Sodium Sulfate
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For elements with more than one possible charge (transition metals)…
Use the charge on the anion to determine the charge on the cation!
Example:
Fe
2
(CrO
4
)
3
+6/2=+3 -2(3)=-6
Iron (III) Chromate
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Example:
Sn(CO
+4
3
)
-2(2)=-4
2
Tin (IV) Carbonate
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Example:
Cu
3
P
+3/3=+1 -3
Copper (I) Phosphide
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Criss Cross Short Hand Method
Just use the number of the charge (not the charge itself) and criss cross as shown below. You will note that the overall charge is neutral, as the total positive charge of the metals offsets the total negative charge of the nonmetal.

Acids are ionic compounds that contain H +1 as their cation.
Acids are named based on their anion .
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“-ide”  hydro ___ ic acid
The root name of the anion goes here
(remove-ide)
Example: H
2
S Sulfide (S -2 ) is the anion!
Hydrosulfuric acid
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“-ate”  ___ ic acid
Example: H
2
SO
4
Sulfate (SO
4
-2 ) is the anion!
Sulfuric acid
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“-ite”  ___ ous acid
Example: H
2
SO
3
Sulfite (SO
3
-2 ) is the anion!
Sulfurous acid
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Mnemonic devices to help you remember Acid
Nomenclatire
#1) “eight is great”er number of oxygens
“ite” is slight” less number of oxygens
#2) Chemistry “Diseases” (joke..I am suffering from eight-ic-ite-ous or)....
“ate” -ic “ite”-ous
SO
4
= sulfate
H
2
SO
4
Sulfuric Acid
SO
3
= sulfite
H
2
SO
3
Sulfurous Acid or lessous
NO
2
= nitrite icmore
NO
3
= nitrate
HNO
2 nitrous acid HNO
3 nitric acid
H
3
PO
3
PO
3
= phosphite PO
4
= phosphate
= phoshporous Acid H
3
PO
4
= phosphoric Acid

Use the reverse to determine the anion and balance out the charges for a neutral compound.
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Hydrophosphoric acid All acids contain a H +1 charge as the cation!
H +1 P -3
H +1
H +1
H
3
P
Original ending “ide”
Ask yourself, “What was the original ending?”
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Chromic acid
Original ending “ate”
H +1 (CrO
4
) -2
H +1
H
2
CrO
4
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mono – 1 hexa – 6 di – 2 hepta – 7 tri – 3 tetra – 4 penta – 5 octa – 8 nona – 9 deca - 10
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 Use the prefixes to indicate how many of each element is in one molecule.
 Change the ending on the second element to “-ide”
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N
2
O
4 dinitrogen tetraoxide
CO carbon monoxide
SiO
2 silicon dioxide
If there is only one of the first element, do not write mono.
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 Use the prefixes to determine the subscripts
Examples: trisulfur hexafluoride
S
3
F
6 carbon pentaoxide CO
5
P
4
O
2 tetraphosphrous dioxide
DO NOT REDUCE!
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