Representing Ionic Compounds

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

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

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

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)

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.

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

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.

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

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