1. IONIC COMPOUNDS

2. Review
Valence electrons = electrons in outer energy level, participate in chemical bonds
Chemical bond = the force that holds two atoms together
Forming Ions: positive (cation) = formed by losing electrons, negative (anion) = formed by gaining electrons

3. Octet Rule & Lewis Dot Diagrams
Octet rule : atoms tend to gain, lose, or share electrons in order to acquire a full set (8) valence electrons
Lewis Dot Diagrams: valence electrons places as dots around the element symbol

4. Forming an Ionic Bond
Type 1: Binary Ionic compounds = contain only two different elements
Ex: NaCl, MgBr2
Type 2: Polyatomic Ionic compounds = contain polyatomic ions, three or more elements
Ex: NaOH, NH4Cl, H2SO4
Ions
Monatomic Polyatomic
Composed of a Single atom
Charged group of atoms

5. Naming Ionic Compounds
1. Name the cation first. It is just the name of the element.
2. Name the anion second.
If it is a monatomic anion (only one element) change the ending of the element name to ide. Example: Chlorine = chloride
If it is a polyatomic anion (multiple elements) use the name provided on your blue common ions handout. Example: SO42- = Sulfate

6. Practice Name the following ionic compounds: NaF KBr AgCl KNO2 Fe(CN)2
MgS2O3

7. Writing Ionic Formulas Using the Empirical Formula
Empirical Formula = ratio of ions in a compound
 simplify to lowest whole #’s
1. Determine the charge of each ion.
2. Always write the cation (positive ion) first.
3. Write the anion (negative ion) second.
4. Determine how many of each ion you need to have the charges balance. (criss-cross method)
5. Use parentheses around the ions to separate if necessary.
6. Write the amount of each ion you need as a subscript after the parenthesis.

8. Practice Write the formulas for the following ionic compounds:
Calcium chlorate
Potassium iodide
Aluminum bromide
Aluminum carbonate
Sodium sulfate
Magnesium phosphate

9. Al2(CrO4)3 Counting Atoms
How do you determine the number of atoms of each element in an ionic compound?
Multiply the number of atoms in the ion by the number of ions in the compound.
Al2(CrO4)3