1. Chemical Bonding – Ionic Bonds Part 2

2. Naming Ionic Compounds
Ionic compounds all have two-word names
The first word in the name is the same as the name of the first ion (for example, sodium, ammonium, potassium, etc)
The second word in the name is either:
1. If the second ion is polyatomic, it is just the name of the polyatomic ion
2. If the second ion is an element, the end of the element’s name changes to –ide
Example: chlorine  chloride
oxygen  oxide
If the metal ion is transition metal, you MUST include the charge on the transition metal in parenthesis between the two words

3. Practice Naming Ionic Compounds
Na2CO3 --
CaSO4 --
KBr --
MgS --
BeCl2 --
NH4F –
CuF
CuCl2

4. Writing Ionic Compounds From Name
If I have an ionic compound, for example, potassium sulfate, how do I know what the formula is?
REMEMBER THAT THE COMPOUND MUST BE NEUTRAL
So, I have Potassium, K, which will lose 1 electron and gain a positive charge, making it K+
And, I have Sulfate, a polyatomic ion, which has a charge of -2
Therefore, I need 2 potassium ions to balance out my one sulfate ion, making my formula, K2SO4
-- this is why we have subscripts in chemistry

5. What About. . .
What if I have to put multiple polyatomic ions in a compound, for example, magnesium nitrate?
Magnesium has a charge of +2
Nitrate is polyatomic and has a charge of -1
Therefore, we need 2 nitrate ions for each magnesium
In this case, we put the entire polyatomic ion in parenthesis and put the subscript outside the parenthesis
Our answer would be Mg(NO3)2

6. Practice Writing Formulas
Write the formulas for the following compounds:
Calcium phosphate --
Lithium oxide --
Zinc (I) sulfate --

7. Properties of Ionic Compounds
Ionic compounds have the following properties:
Crystal Pattern – every ion is attracted to all other ions with the opposite charge
-- this results in a repeating 3-dimensional crystal pattern

8. Properties of Ionic Compounds cont’d
High Melting Point – the attraction in the crystal pattern leads to very strong bonds, making it hard to break apart ionic compounds
-- ionic compounds melt at high temperatures
Conductivity – when dissolved in water, ionic compounds conduct electricity
-- in water, the bonds dissociate (fall apart), leaving lots of ions to carry charge
Solid ionic compounds do not conduct electricity very well
-- melted ionic compounds do conduct electricity fairly well