1. Chapter 5 Types of Compounds
5.1 Ionic Compounds
5.2 Molecular Substances

2. 5.1 Ionic Compounds - Objectives
Apply ionic charge to writing formulas for ionic compounds
Apply formulas to name ionic compounds
Interpret the information in a chemical formula

3. Formula and Names of Ionic Compounds
Ionic compounds are composed of ions bound by ionic bonds usually a metal and a nonmetal
Ionic bonds are strong attractive forces
Ionic compounds are usually solids at room temperature
Many are crystalline
Difficult to melt  high melting points
When melted or in solutions they conduct electricity

4. Binary Ionic Compounds
Binary compound- composed of two elements
Binary ionic compounds- composed of two different ions
NaCl KI
CaF2

5. Ions Positively charged = cation Negatively charged = anion
When naming the name stays the same
Calcium ion
Sodium ion
Negatively charged = anion
When naming the name is changed
Ending becomes –ide
Chloride ion
Sulfide ion

6. Naming Binary Ionic Compounds
Always write the cation first followed by the anion.
Make sure the anion ending is modified to –ide.
Na Cl-  Sodium Chloride
K I-  Potassium Iodide

7. Writing Binary Ionic Compound Formulas
Compounds are always neutral
Net ionic charge must always be zero
Use subscripts to indicate when more than one ion of an element is present
When only one ion is present, no subscript is needed
NaCl
When more than one is present subscripts are need
CaF2  1 Calcium ion and 2 fluoride ions

8. Binary Ionic Compounds
Always written in the smallest whole number ratio – Formula Unit
Example Calcium Fluoride

9. Predicting Charges on Ions
Oxidation Number- the charge on the ion
Metals always lose electrons when they form ions
Nonmetals always gain electrons when they form ions
Periodic table can be used to predict the oxidation number (charge of ion) of some elements

10. Table 5.1 Ionic Charges of Representative Elements
Group Number Oxidation Number Examples
Metals
Li+, Na+, K+
Mg2+, Ca2+
B3+, Al3+
Nonmetals
N3-, P3-
O2-, S2-
F-, Cl-, Br-, I-

11. Let’s Try It!
Write the formula for an ionic compound containing sodium and sulfur.
What is the name of the compound?

12. Write a formula for each of the following compounds
Lithium oxide
Calcium bromide
Sodium oxide
Aluminum sulfide

13. Write the formula & name for the compound formed from each of the following pairs of elements.
Barium and oxygen
Strontium and iodine
Lithium and chlorine
Radium and chlorine

14. 5.1 Ionic Compounds

15. Compounds Containing Polyatomic Ions
Polyatomic Ions-an ion that has two or more different elements
Group of atoms are covalently bonded together when the atoms share electrons
The individual atoms do not have a charge, but the group as a whole has an overall charge

16. Polyatomic Ions
Ionic compounds may contain positive metal ions bonded to negative polyatomic ions or negative nonmetal ions bonded to positive polyatomic ions

17. Writing formulas using Polyatomic Ions
Treat the polyatomic ion as one unit or a single ion
Write the cation ion first followed by the anion
When more than one polyatomic ion is needed to make the net charge zero you place it in parentheses and then add the subscript.

18. Common Polyatomic Ions
1- charge
2- charge
3- charge
Formula
Name
H2PO4-
C2H3O2-
HSO3-
HSO4-
HCO3-
NO2-
NO3-
CN-
OH-
MnO4-
ClO-
ClO2-
ClO3-
ClO4-
Dihydrogen phosphate
Acetate
Hydrogen sulfite
Hydrogen sulfate
Hydrogen carbonate
Nitrite
Nitrate
Cyanide
Hydroxide
Permanganate
Hypochlorite
Chlorite
Chlorate
Perchlorate
HPO42-
C2O42-
SO32-
SO42-
CO32-
CrO42-
Cr2O72-
SiO32-
Hydrogen phosphate
Oxalate
Sulfite
Sulfate
Carbonate
Chromate
Dichromate
Silicate
PO43-
PO33-
Phosphate
Phosphite
1+ charge
NH4+
H3O+
Ammonium
Hydronium

19. Naming Polyatomic Ions
Follows the same rules as naming binary
Name the cation first and then the anion
You do not change the ending of the anion for polyatomic ions
-ite indicates one less oxygen atom than -ate
-ate indicates one more oxygen atom than –ite
Does not tell you the number of oxygen atoms in the ion

20. Let’s Try It!
Write the formula for the compounds made from each of the following ions.
Ammonium and sulfite ions
Calcium and hydrogen phosphate ions
Ammonium and dichromate ions
Barium and nitrate ions

21. Let’s Try It! Write the formula for each of the following compounds.
Sodium phosphate
Magnesium hydroxide
Ammonium phosphate
Potassium dichromate

22. Compounds of Transition Elements
Transition elements are groups 3 through 12 in the periodic table
Form positive ions, but they form more than one type of positive ions
Copper forms two ions one with a +1 charge and one with a +2 charge
The way they are distinguished is with roman numeral. Copper (I) and Copper (II)

23. Names of Common Ions of Selected Transition Elements
Chemical Name
Chromium
Cr2+
Cr3+
Cr6+
Chromium (II)
Chromium (III)
Chromium (VI)
Cobalt
Co2+
Co3+
Cobalt (II)
Cobalt (III)
Copper
Cu+
Cu2+
Copper (I)
Copper (II)
Gold
Au+
Au3+
Gold (I)
Gold (III)
Iron
Fe2+
Fe3+
Iron (II)
Iron (III)
Manganese
Mn2+
Mn3+
Mn7+
Manganese (II)
Manganese (III)
Manganese (VII)
Mercury
Hg+
Hg2+
Mercury (I)
Mercury (II)
Nickel
Ni2+
Ni3+
Ni4+
Nickel (II)
Nickel (III)
Nickel (IV)

24. Let’s Try It!
Write the formula for the compounds made from each of the following pairs of ions.
Copper (I) and sulfite
Tin (IV) and fluoride
Gold (III) and cyanide
Lead (II) and Sulfide

25. Let’s Try It! Write the names of the following compounds. Pb(NO3)2
Mn2O3
Ni(C2H3O2)2
HgF2

26. Hydrates
Many ionic compounds are prepared by crystallization from a water solution, and water molecules become a part of the crystal.
Hydrates- a compound in which there is a specific ratio of water to ionic compound.
In hydrate, the water molecules are chemically bonded to the ionic compound

27. Hygroscopic
Hygroscopic- a substance that absorbs water molecules from the air to become a hydrate.
Sodium Carbonate
Some substances are so hygroscopic that they take up enough water from the air to dissolve completely and form a liquid solution. These compounds are called deliquescent.
Sodium Hydroxide

28. Writing Formulas for Hydrates
When writing a formula for a hydrate you place a dot in the formula between the ionic compound and the water.
CaSO4 · 2H2O
What this means is for every one calcium sulfate there are two water molecules in the hydrate.

29. Naming Hydrates
You use the regular name for the compound followed by the word hydrate, to which a prefix is added.
1 = mono-
2 = di-
3 = tri-
4 = tetra-
Exp.: CaSO4 · 2H2O  Calcium sulfate dihydrate

30. Anhydrous
Anhydrous – a compound in which all the water has been removed, usually by heating
In some cases the anhydrous compound may be a different color than the hydrate.
Copper (II) sulfate pentahydrate is blue compound when it is heated to remove the water and become anhydrous it turns white, this compound is Copper (II) sulfate anhydrous

31. Homework
P #1-5, 7, 8