1. Warm Up
Write the usual ionic charge for the following:
F Al
O Zn
Na Ag Mg Ar

2. Ionic Compounds
All contain a cation (usually a metal) and an anion (a nonmetal)
Are electroneutral = no net charge
The positives and negatives must balance out
Combine anions and cations to reach net charge of zero
Ionic Bond – force of attraction between oppositely charged ions: Makes for a very strong bond!

3. Ionic compounds: formed by giving/taking of electrons
Ionic compounds: formed by giving/taking of electrons. Ions are held together by the attraction of opposite charges! (Do you remember electrostatic forces?)
Makes a “crystal lattice” with no true beginning or end to the compound. All of its parts are interconnected. There are no individual molecules here!

4. Properties of Ionic Compounds:
Crystal lattice structure
Strong attraction between cations and anions
Very hard, but brittle structures
High melting and boiling points
Generally solid at room temperature
Conduct electricity when melted (molten) or in aqueous solution (dissolved in water).

5. Naming Ions and Ionic Compounds
Cation = just use the name of element
Lose electrons = Positively charged
Ex. Rubidium loses one electron = Rb ion, Rb+
Ex. Strontium loses two electrons = Sr ion, Sr2+
Anion = use name of element with -ide ending
Gain electrons = negatively charged
Ex. Chlorine becomes chloride ion, Cl-
Ex Sulfur gains two electrons = sulfide ion, S2-
Ex. Ionic Compound Names
Rb+ + Cl- = RbCl = rubidium chloride
Na+ + S2- = Na2S = sodium sulfide
K+ + N???
= K3N = potassium nitride

6. Naming Transition Metals
Many transition metals have more than one possible charge
Stock system: Uses a roman numeral to show the charge of the ion
Ex.
Cu+ = copper (I) ion
Cu2+ = copper (II) ion

7. Stock System Examples Fe3+ + Cl- FeCl3 iron (III) chloride
Fe2+ + Cl- FeCl2 iron (II) chloride
Cu+ + Cl- CuCl copper (I) chloride
Cu2+ + O2- CuO copper (II) oxide

8. Warm Up: Write each ion and the formula of the following:
1) sodium fluoride
2) sodium oxide
3) iron (III) oxide
4) iron (II) sulfide

9. Answers:
1) sodium fluoride
Na+ F-
2) sodium oxide
Na+ O2-
3) iron (III) oxide
Fe3+ O2-
4) iron (II) sulfide
Fe2+ O2-

10. Now, write the neutral formula for the compound!
1) sodium fluoride
Na+ F-
2) sodium oxide
Na+ O2-
3) iron (III) oxide
Fe3+ O2-
4) iron (II) sulfide
Fe2+ O2-
How to solve???

11. Ionic Formulas  sodium chloride criss-cross method  calcium sulfide
Ionic formulas are found by combining the ions in simplest proportion using the
criss-cross method
Steps:
Write the ions present
Assign charges
Criss-cross the charges
If 1 is a subscript, do not write it
The formulas for ionic compounds gives us the smallest whole number ratio of the ions (So if the numbers are the same, reduce!)
Check your work: The sum of all charges in the formula has to be zero
 sodium chloride
 calcium sulfide
magnesium chloride
iron (III) oxide
lithium phosphide

12. Examples: Naming Compounds
1. PbF FeO
Pbx Fx Fex Ox
3. Cr2O SnP
Crx Ox Snx Px