1. Ionic Compounds

2.  Pure substances  formed as a result of the attraction between particles of opposite charges, called ions  High melting point  Good electrical conductivity  Distinct crystal shape

3.  All are solids at room temperature  When an ionic compound is melted or dissolved in water, it will conduct electricity  These properties led to the study of electrochemical cells  That work led to the invention of batteries

4. When ionic compounds are dissolved in water, the metal and non-metal form an aqueous solution of ions Ion Is an atom or a group of atoms that has become electrically charged through the loss or gain of electrons

5. Ion Charges To indicate ions in written notation  A plus sign (+) or a minus sign(-) is placed to the upper right of the elements symbol  In Superscript position (above) ElementIon ChargeIon Notation Hydrogen 2- Sodium 2+Mg 2+ Fe 2+ or Fe 3+ Copper

6. Polyatomic ions (poly – means “many”) Groups of atoms acting as one Examples:CarbonateCO 3 2- NitrateNO 3 - PhosphatePO 4 3- AmmoniumNH 4 +

7. Naming Ionic Compounds There are two Rules: 1. Chemical name of the metal (positive) ion goes first, followed by the name of the non-metal (negative) ion 2. Name of the non-metal (negative) ion changes its ending to ide Example: NaClSodium Chlorine Sodium chloride LiCl (s) Ca 3 P 2 (s)

8. Naming Ionic Compound Video Exception: If the negative ions are polyatomic ions, the name remains unchanged Example: Ca 2+ CO 3 2- Calcium carbonate CuSO 4 (s) Na 3 PO 4 (s)

9. Some metal ions have more than one ion charge. To show which ion is being used in a chemical name, a Roman numeral is added Example: Fe2+O2-= iron (II) oxide Fe3+O2-=iron (III) oxide PbS 2 (s) Naming Ionic Compound Video PbS (s) Na 2 O (s) Fe 2 O 3 (s)

10. Using Ion Charges and Chemical Name to Write Formulas Step 1Calcium Chloride a) Print the metal element’s symbols with the ion charge b) Print the non-metal element’s symbol with the ion charge Ca 2+ Cl 1- Step 2 Balance the ion charges. Now you know how many atoms of each element you need to include in the formula Ca 2+ Cl 1- Cl 1- ( 2+ ion charge of one calcium)(must be two chlorine atoms each with 1- ion charge) Step 3 Write the formula by indicating how many atoms of each element are in it. Do not include the ion charge in the formula Place the number of atoms of each element in a subscript after the element’s symbol CaCl 2(s)

11. Lithium Oxide Sodium Fluoride Copper (II) Phosphide Iron (III) Chloride Writing formula video