1. IONIC COMPOUNDS

2. IONIC COMPOUNDS 1. What are they?
Formed when positive metal ions (cations) join to negative non-metal ions (anions) usually in solution. (This means that the ions are aqueous (aq.) – in water!)
They can also form at high temperatures in the gaseous state but this is not as common as solution formation.
RECALL: Ions are formed when an atom gains or loses e- from their outer orbital to form a more stable charged particle (Octet Rule: pp. 229)

3. Positive charges= Negative charges
2. Forming Ionic Compounds
Ionic compounds are overall neutral (have no charge); that is, the sum of the positive charges (metal ions) must equal the sum of the negative charges (non-metal ions)
Positive charges= Negative charges
Recall: Metals are e- givers and their ions are positively charged while non- metals are e- takers and their ions are negatively charged.
When they meet – they balance out to neutral!

4. Examples of ionic compounds being formed:
eg.: Sodium metal ions reacting with chloride ions in solution
eg.: Magnesium ions reacting with bromide ions in solution
eg.: Lithium ions reacting with oxide ions
It’s all about balancing the charges so the compound ends up neutral!!

5. Beryllium Oxide : Calcium Nitride : Sodium Oxide :
This is called an ionic equation.
It shows the ions from which an ionic compound is formed, including the smallest whole number ratio of ions in the compound!
You try! Show the Ionic equation for the formation of…
Silver Chloride :
Beryllium Oxide :
Calcium Nitride :
Sodium Oxide :

6. 3. Finding Ionic Compound Formulas!!
Find the Formula for…
Magnesium Phosphide
All we are doing it trying to balance out all the charges to the lowest whole number so that the ionic compound ends up being neutral!!
*RECALL… the metal is always written first in the formula!

7. A short-cut… The “Criss-cross Method”
Another way to predict the formula is to “criss- cross” the charge on the metal to produce the number of non-metals required (i.e. the subscript behind the non-metal), and vice versa
Mg 2+
P 3-
Mg 3 P 2

8. Now you try: Predict the formula for calcium oxide
Calcium is Ca2+ Oxygen is O2–
Formula Ca2O2
This is simplified to CaO
Ca2+
O-2

9. Multi-Valent Ions
Some transition metals are multivalent, meaning they have more than one ion form.
In the name of the compound, Roman Numerals are used following the cation to indicate which ion was used
For example:
Manganese (II) Bromide

10. More Practice Questions:
Hebden (p. 76) # 99,108, 105, 113, 114,124,127,144, 149, 153, 161

11. 4. Finding Poyatomic Ion Formulas
Recall: Polyatomic ions are two or more different atoms chemically combined and acting like a single charged particle (ion).
  Eg.:
Eg.: Sodium ions reacting with nitrate ions
Eg.: Calcium ions reacting with hydroxide ions
Note: Use brackets for polyatomic ions if more than 1 is present in the molecule.
Eg.: Ammonium ions reacting with dichromate ions

12. Practice KNO3 Ca(OH)2 Ag2SO4 NH4CN Pb(CO3)2 NOW YOU TRY IT!
Hebden (p. 76) #95, 101, 103, 119, 125, 131, 135, 141,147, 156,158
Practice
Give the Formula for:
Potassium nitrate
Calcium hydroxide
Silver sulphate
Ammonium cyanide
Lead (IV) carbonate
KNO3
Ca(OH)2
Ag2SO4
NH4CN
Pb(CO3)2

13. International Union of Pure and Applied Chemistry
5. Names of Ionic Compounds using the IUPAC method (Nomenclature)
The metallic or positive ion is always named first and their names DO NOT change
Metals that can have more than one charge or valence need a Roman numeral in the name in order to indicate the charge on the ion. eg.: Iron (II) Fe2+ Lead (IV) Pb4+
Non-metal ions that are single elements change their endings to "ide“. eg.: Chlorine chloride Oxygen oxide
Polyatomic ions do not change their names. ( You know one is there if there are more than 2 capital letters in the formula!)
International Union of Pure and Applied Chemistry

14. PbCl2 PbCl4 Lead (II) chloride Lead (IV) chloride
Try This…MULTI-VALENT METALS
Eg.: Find the charge on the Pb ion in:
PbCl PbCl4
Lead (II) chloride
Lead (IV) chloride

15. Recall… Mono Di Tri Tetra Penta Hexa Hepta Octa Nona Deca 1 2 3 4 5 67 8 9 10
Mono Di
Tri
Tetra
Penta
Hexa
Hepta
Octa
Nona
Deca

16. 6. Naming/Formulas for HYDRATES!
Hydrates are molecules that include WATER in their structure.
Eg. CuSO4·5H20
To name them… it’s easy…
a) Name the Ionic/polyatomic compound first…
b) Then use the proper prefix to indicate how many water (hydrate) molecules there are…
So… If 5 waters = Pentahydrate
If 3 waters = Trihydrate
So… the full name of CuSO4·5H20
Copper (II) Sulphate Pentahydrate

17. What would you Name… Zn(CH3COO)2•2H2O Zinc Acetate Dihydrate
What about the formula for …
Calcium Nitrate Tetrahydrate
Ca(NO3)2 • 4H2O

18. You try…
Hebden Pg. 75 # 19,47,53, 59, 94,111,116,129,140,151,160

19. Practice Questions:
Hebden (p. 75/76 evens 9 only do the ionic/Polyatomic ones – not covalent compounds!!