Chapter 2 The Material World Molecules Chapter 2 The Material World

Forming Ionic Compounds (with transition metals)

What are transition metals? Transition metals are the metals located in the middle of the periodic table (in the “B” section)

What are transition metals? Transition metals are the metals located in the middle of the periodic table (in the “B” section) These metals have various oxidation states In other words: these are elements that can take on different charges Fe2+ Fe3+

Examples These are the possible oxidation states (charges) that the element can take on

These are the most common oxidation states (charges) that the element can take on

Naming Ionic Compounds with Transition Metals RULE: Transition Metal Name (Roman numeral of oxidation state) + Non-Metal Name (modified ide ending) Still ignoring the subscripts! Examples: Cu2O  Copper (I) Oxide CrCl3  Chromium (III) chloride MnO  Manganese (II) oxide

How do we know which oxidation state to use? Backwards Crossover Method!

Backwards Crossover Method Cu O 2 1 Means that Copper has a charge of +1 (because it’s a metal and donates the electron) Copper (I) oxide

Backwards Crossover Method Cr Cl 1 3 Means that Chromium has a charge of +3 (because it’s a metal and donates the electrons) Chromium (III) chloride

Backwards Crossover Method 2 2 Mn O But wait! We KNOW oxygen has a charge of -2 1 1 That means manganese must have a charge of +2 Manganese (II) oxide

Forming Ionic Compounds (with polyatomic ions)

What are polyatomic ions? Polyatomic ions are a group of atoms that, as a group, have a charge Polyatomic = multiple atoms Ions = charged particles This means that these groups can form ionic bonds with other ions (metals and non-metals)!

Ion (chemical formula) Name NH4 + ammonium CO3 -2 carbonate NO2 - Nitrite HCO3 - hydrogen carbonate (often also called bicarbonate) NO3 - nitrate ClO - hypochlorite SO3 -2 sulfite ClO2- chlorite SO4 -2 sulfate ClO3 - chlorate HSO4 - hydrogen sulphate (bisulfate is a widely used common name) ClO4 - perchlorate OH - hydroxide C2H3O2 - acetate CN - cyanide MnO4 - permanganate PO4 -3 phosphate Cr2O7 -2 dichromate HPO4 -2 hydrogen phosphate CrO4 -2 chromate H2PO4 - dihydrogen phosphate O2 -2 peroxide

Naming Ionic Compounds with Polyatomic Ions RULE: Same as for binary ionic compounds but use the name of the polyatomic ion - Never change the ending of the polyatomic ion’s name Examples: AlPO4  Aluminum phosphate Ba(CN)2  Barium cyanide NH4NO3  Ammonium nitrate Still ignoring the subscripts!

Naming Ionic Compounds – Polyatomics + Transition metals! FeSO4 Iron (II) sulfate Cu(ClO3)2 Copper (II) chlorate