Ionic Formulas

What are ions? Review: What’s the difference between monatomic and polyatomic ions? Monatomic Ion – ion with only one element Polyatomic Ion – ion with more than one element

WARNING! We’re going to start out with JUST MONATOMIC IONS. We’ll work on POLYATOMIC IONS later.

Ionic Compound Ionic Compound – a compound in which positive and negative ions attract each other to keep matter together - Overall charge of the compound is neutral

Ionic Formula How do we represent an ionic compound? Ionic Formula – Similar to a chemical formula, this shows what ions (AND how many of each ion) are in an ionic compound

Writing Ion Practice Look at the ions and formulas listed below. Do you notice any patterns? IonsFormula Li + F - LiF Na + Cl - NaCl Be 2+ O 2- BeO Mg 2+ O 2- MgO Al 3+ N 3- AlN IonsFormula Li + O 2- Li 2 O Na + N 3- Na 3 N Mg 2+ F - MgF 2 Al 3+ Cl - AlCl 3 Be 2+ N 3- Be 3 N 2

Writing Formulas – Equal Charges If the cation and anion charge are the same value: IonsFormula Li + F - LiF Na + Cl - NaCl Be 2+ O 2- BeO Mg 2+ O 2- MgO Al 3+ N 3- AlN Drop the charges and write the elements Cation first, then anion

Writing Formulas – Equal Charges Example 1) Lithium Fluoride Li + F - LiF

Writing Formulas – Equal Charges Example 2) Magnesium Oxide Mg 2+ O 2- MgO

Writing Formulas – Different Charges If the cation and anion charge are not equal, 1 cation and 1 anion will not form a neutral compound. IonsFormula Li + O 2- Li 2 O Na + N 3- Na 3 N Mg 2+ F - MgF 2 Al 3+ Cl - AlCl 3 Be 2+ N 3- Be 3 N 2

Writing Ionic Formulas STEP 1) Write the cation first, then the anion. EXAMPLE Aluminum Chloride Al 3+ Cl -

Writing Ionic Formulas STEP 2) Drop the + and – (but NOT the numbers!!) EXAMPLE Aluminum Chloride Al 3 Cl 1

Writing Ionic Formulas STEP 3) Cross the charges. EXAMPLE Aluminum Chloride Al 3 Cl 1 Al 1 Cl 3

Writing Ionic Formulas STEP 4) Drop any “1”. EXAMPLE Aluminum Chloride Al 1 Cl 3 AlCl 3

Writing Ionic Formulas STEP 1) Write the cation first, then the anion. EXAMPLE Beryllium Nitride Be 2+ N 3-

Writing Ionic Formulas STEP 2) Drop the + and – (but NOT the numbers!!) EXAMPLE Beryllium Nitride Be 2 N 3

Writing Ionic Formulas STEP 3) Cross the charges. EXAMPLE Beryllium Nitride Be 2 N 3 Be 3 N 2

Writing Ionic Formulas STEP 4) Drop any “1”. EXAMPLE Beryllium Nitride Be 3 N 2

Writing Ionic Names Rule: Cation is written as its element’s name. Anion name ends in –ide. **Sometimes we have to figure out the name from the formula. Given the ionic formula, work backwards to figure out the ions.

Names – Example 1 CaBr 2 Ca 2+ Br - Calcium Bromide

Names – Example 2 CoI 3 Co 3+ I - Cobalt (III) Iodide

Names – Example 3 CuS Must have the same charge: Cu 2+ S 2- Copper (II) Sulfide

Group Practice There are 11 stations around the room. Find them all, and write the ionic formula and name for each in your notebook. You will need to bring your Ion Chart with you, since some of the ions are written with NAMES, others with SYMBOLS

Group Practice - Check StationCationAnionIonic Formula Ionic Name 1K+K+ O 2- 2Na + Br - 3Ca 2+ Iodide 4CalciumS 2- 5Al 3+ Fluoride 6Iron (III)Te 2- 7Ag + P 3-

Group Practice - Check StationCationAnionIonic Formula Ionic Name 8Li 3 N 9Ga 2 Se 3 10Cu 2 O 11CuO

Group Practice - Check StationCationAnionIonic Formula Ionic Name 1K+K+ O 2- K2OK2OPotassium Oxide 2Na + Br - NaBrSodium Bromide 3Ca 2+ IodideCaI 2 Calcium Iodide 4CalciumS 2- CaSCalcium Sulfide 5Al 3+ FluorideAlF 3 Aluminum Fluoride 6Iron (III)Te 2- Fe 2 Te 3 Iron (III) Telluride 7Ag + P 3- Ag 3 PSilver Phosphide

Group Practice - Check StationCationAnionIonic Formula Ionic Name 8Li + N 3- Li 3 NLithium Nitride 9Ga 3+ Se 2- Ga 2 Se 3 Gallium Selenide 10Cu + O 2- Cu 2 OCopper (I) Oxide 11Cu 2+ O 2- CuOCopper (II) Oxide

Independent Practice Fill out the Monatomic Ions Practice