Read
pg 154-170
Chapter 5: Types of Compounds
54.1
5.1 – Ionic Compounds
Objectives:
1. Apply ionic charge to writing formulas for ionic
compounds.
2. Apply formulas to name ionic compounds.
3. Interpret the information in a chemical formula.
A. Formulas and Names of Ionic Compounds
54.2
NaCl
sodium chloride
Solid
Brittle
High Melting Point
Water Soluble
Conductive
A. Formulas and Names of Ionic Compounds
54.3
Brittle:
Like charges repel
1
54.4
A. Formulas and Names of Ionic Compounds
http://www.personal.kent.edu/~cearley/ChemWrld/jmol/crystals/crystals.htm
54.5
A. Formulas and Names of Ionic Compounds
Water Soluble
http://www.chem istry.wustl.edu/~edudev/LabTutorials/Water/PublicWaterSupply/dissolving_movie.html
54.6
A.1. Binary Ionic Compounds
Binary Ionic Compounds: Contains only two elements.
-ide added to nonmetal.
compound
NaCl
metal
nonmetal
name
sodium
chlorine
sodium chloride
MgO
magnesium
oxygen
magnesium oxide
CaF2
calcium
fluorine
calcium fluoride
2
54.7
A.1. Binary Ionic Compounds
Subscript: number of ions per compound.
NaCl
one Na for every one Cl.
Na
Cl
F
CaF2 one Ca for every two F.
Ca
F
Al2O3 two Al for every three O.
Al
O
Al
O
O
54.8
A.1. Binary Ionic Compounds
Formula Unit: Represents smallest ratio of ions.
Mg+2
O -2
Ca+2
S -2
Mg2O2
Ca2S2
MgO
CaS
54.9
A.1. Binary Ionic Compounds
Sum of ions must equal zero.
NaCl
Na +1 Cl -1
+1
Na
Na1
+1
(1)(1) = 1
Cl1
-1
Cl
-1
(1)(-1) = -1
1-1=0
3
54.10
A.1. Binary Ionic Compounds
Sum of ions must equal zero.
Ca +2 F -1
CaF2
-1
Ca1+2
+2
Ca
F2-1
F
F
(1)(2) = 2
-1
(2)(-1) = -2
2-2=0
54.11
A.1. Binary Ionic Compounds
Sum of ions must equal zero.
-2
Al +3
Al2O3
Al2+3
O -2
O3-2
(2)(3) = 6
+3
Al
O
+3
Al
O
O
(3)(-2) = -6
-2
-2
6-6=0
54.12
A.1. Binary Ionic Compounds
The Criss-Cross Trick
Ca +2 F -1
Ca
F2
CaF2
Al +3
Al2
O -2
O3
Al2O3
4
54.13
A.2. Predicting Charge on Ions
Oxidation Numbers: Charge of Ion.
C
Si
Transition metal oxidation numbers
can not be predicted by group number.
54.14
A.3. Compounds Containing Polyatomic Ions
Polyatomic Ion: Contains two or more different elements
covalently bonded together. Can have
either a positive or negative charge.
protons
electrons
+9
-10
overall charge -1
A.3. Compounds Containing Polyatomic Ions
54.15
H
+1
O
+8
OH -
Na +
5
A.3. Compounds Containing Polyatomic Ions
54.16
Cations: Positively
charged ions
A.3. Compounds Containing Polyatomic Ions
54.17
Anions:
Negatively
charged ions
A.3. Compounds Containing Polyatomic Ions
54.18
6
A.3. Compounds Containing Polyatomic Ions
54.19
Cation
Anion
Ionic
Compound
Name
Na +1
NO2-1
NaNO2
sodium nitrite
Mg +2
CO3-2
MgCO3
magnesium carbonate
Na +1
SO4-2
Na2SO4
sodium sulfate
Mg +2
NO3-1
Mg(NO3)2
magnesium nitrate
A.4. Compounds of Transition Elements
54.20
A.4. Compounds of Transition Elements
54.21
Transition elements can form
multiple oxidation states.
7
54.22
A.4. Compounds of Transition Elements
Fe +3
Fe +2
SO4 -2
FeSO4
Fe2(SO4)3
Iron (II) Sulfate
Iron (III) Sulfate
A.4. Compounds of Transition Elements
54.23
A.5. Hydrates
54.24
Hydrate: Water is bound to ionic compound.
Cobalt (II) chloride hexahydrate
CoCl2 . 6H2O
Anhydrous: Water removed.
Cobalt (II) chloride
CoCl2
8