Lecture 3.1 Oxidation and Naming

Ions are anything that has a charge The charges are sometimes called oxidation numbers, or oxidation states The oxidation number of compounds always add up to 0 Ex. NaCl, MgCl2

Pure elements are neutral, and have an oxidation number of 0 Ex. Ag, Na, S Diatomic elements also have an oxidation number of 0 (memorize these) Ex. H2, N2, O2, F2, Cl2, Br2, I2

The Periodic Table can give us a hint to the oxidation numbers of ions Elements between 3A and 7A may have different oxidation numbers! IA IIA IIIA IVA VA VIA VIIA +1 +2 +3 +4/-4 -3 -2 -1

Practice What is the oxidation numbers for the following atoms, if they were ions? Ca Mg O Cl Na N

Transition metals Many transition metals can have multiple oxidation numbers Depending on the oxidation number, the metals are named differently There are two ways to name the metals, Latin roots (old way), and Stock Method (new way)

Copper, Cu, can have an oxidation of +1 or +2 Cu+ will be copper (I) Cu2+ will be copper (II) Iron, Fe, can have an oxidation of +2 or +3 Fe2+ will be iron (II) Fe3+ will be iron (III)

For Stock Method, the Roman Numerals inside parentheses shows the oxidation number. I, II, III, IV, V, VI

Practice What is the oxidation number for the following atoms? Gold (III) Silver (II) Lead (IV)

How to name ionic compounds Binary ionic compounds are formed when a monoatomic cation (metal) and a monoatomic anion (non-metal) bond to form a compound Ex. NaCl, CaCl2

To name ionic compounds, just add the names of the ions All cations (metals) will have their elemental names Anions (non-metals) are a little more complex

For example, fluorine will become fluoride For monatomic anions, just add a “-ide” suffix to the root of the elemental name For example, fluorine will become fluoride Some common monatomic anion names: Nitride, phosphide, oxide, sulfide, chloride, bromide, iodide

What is the binary ionic compound called What is the binary ionic compound called? Metal name + root of non-metal + ide Potassium chloride Lithium oxide Magnesium bromide Aluminum sulfide KCl Li2O MgBr2 Al2S3

Transitional Metal Practice FeO PbCl4 Co2O3 FeBr3 Iron (II) oxide Lead (IV) chloride Cobalt (III) oxide Iron (III) bromide

Ternary Ionic Compounds Most ternary ionic compounds will contain a monatomic cation, and a polyatomic anion Just combine those two to name the compound

Please memorize the following polyatomic ions and their charges Hydroxide OH- Carbonate CO3 2- Nitrate NO3- Sulfate SO4 2- Bromate BrO3 – Phosphate PO4 3- Ammonium NH4+

Examples of ternary compounds Mg(NO3)2 Magnesium nitrate K2SO4 Potassium sulfate Warning: polyatomic ions are one big unit. Nitrate, NO3-, does not break down into an individual Nitrogen and 3 oxygen.

Writing formulas from names What is the formula for aluminum nitride? Since Al has a charge of 3+, and nitride of 3-, they are already balanced and we can leave the formula to just AlN The ions have to balance each other out! Al3+ N3-

Li+ O2- What is the formula for lithium oxide? Lithium has a charge of 1+, oxide of 2-. We need to balance them. We need TWO lithium to balance the 2- charge of oxide. The formula becomes Li2O Li+ O2-

What is the formula for aluminium oxide? An easy method to balance the ions is to use the “cross over” method. Make sure to drop its charge. The formula will become Al2O3 Two Al will be 6+, Three O will be 6-. They cancel out

When using the cross over method, also make sure to reduce the number Example: Calcium sulfate Ca2+ SO42- Instead of Ca2(SO4)2, it is just CaSO4

What is the chemical formula? Magnesium oxide Calcium fluoride Lithium hydroxide Ammonium sulfate Aluminum carbonate Beryllium phosphate MgO CaF2 LiOH (NH4)2SO4 Al2(CO3)3 Be3(PO4)2 Hydroxide OH- Nitrate NO3- Bromate BrO3 – Cyanide CN- Carbonate CO3 2- Sulfate SO4 2- Phosphate PO4 3-

Fe(OH)3 Fe(OH)2 SnSO4 PbCO3 Iron (III) hydroxide Iron (II) hydroxide Tin (II) sulfate Lead (II) carbonate Fe(OH)3 Fe(OH)2 SnSO4 PbCO3

Make instruction book/comic book on how to name ionic compounds, and write out equations of compounds. Make it colorful and easy to understand. I needs to include sample examples and figures/diagrams/pictures. Title it, put name and period on the cover.