1. Representing Ionic Compounds

2. Ionic Bonding
Ions are atoms that have lost or gained one or more electrons, resulting in a positive or negative charge
Cation = a positively charged ion
Anion = a negatively charged ion

3. Valence Electrons
Electrons in the valence (outer) electron orbital/shell

4. Octet Rule
An octet (8 electrons) in the outer shell makes atoms stable
Electrons are lost, gained or shared to form an octet
All atoms want 8 electrons in their valence (outer) shell
Exception: H and He want 2 electrons
To get 8, they gain or lose electrons, whichever is easier
< 4 valence electrons  lose electrons
> 4 valence electrons  gain electrons

5. Are the following cations or anions?
Chlorine ion Magnesium ion Oxygen ion
Teacher: Draw lewis diagrams from atom to ion to show the gained/lost of electron(s)

6. The Periodic Table & Ionic Charge
Elements in the vertical column families develop the same ionic charges:
Metals tend to lose electrons (form cations).
Non-metals tend to gain electrons (form anions).
Metal cation + non-metal anion = ionic compound.

7. Naming Binary Ionic Compounds
A binary ionic compound is a compound composed of a metal cation and a non-metal anion.
The first part of the name identifies the positive ion, which is the metal cation.
The second part of the name identifies the negative ion, which is the non-metal anion.
The name of the non-metal ion always ends with the suffix –ide
Examples:
Magnesium and phosphorus
Sodium and chlorine
Calcium and bromine
Aluminum and oxygen

8. Writing the Chemical Formulas for Binary Ionic Compounds
Write the symbols with the metal first.
Write the charge above each symbol (without sign +/-).
Cross over the numbers.
Never write the subscript 1.
Write the formula, reduce if possible.

9. Draw Lewis Diagram to show how lithium and fluorine form a compound

10. Practice Elements in ionic compound Ions Name of ionic compound
Chemical Formula of ionic compound
Potassium and bromine
Aluminum and sulphur
Calcium and oxygen
Magnesium and bromine
Calcium and iodine
Aluminum and oxygen
Potassium and chlorine
Magnesium and nitrogen
Sodium and phosphorus
Magnesium and chlorine