Chemistry Nomenclature Binary Ionic Compounds

What are they made of? Binary  Ionic  Example  sodium, Na +  metal chlorine, Cl -  non- metal metal ion + non-metal ion 2 elements

REMEMBER ! Metals tend to Lose electrons and become positive ions (cations). Non-metals tend to gain electrons and become negative ions (anions).

Example 1: Sodium and Fluorine. Draw Bohr-Rutherford diagrams of both atoms.

Na F + - Electro-magnetic Force is created by the TRANSFER of electrons forming a BOND !

Crystal Lattice Structure Each electron which Sodium atom lost, is grabbed by Fluorine atom. There same number of Na + and F - ions, their ratio is 1:1, but ions do not form molecules. Instead, they are tightly packed in crystals with alternative + and – ions.

Example 2 : Aluminum and Chlorine. Draw Lewis diagrams of both atoms Al Cl

Chemical Formula Ex 1: One Sodium for One Fluorine –NaF Ex2 : One Aluminum for Three Chlorine –NaCl 3 Subscript 3 in the formula indicates that it takes 3 Cl atoms to 1 Al atom. With the right subscript, the overall charge of the compound is zero.

Naming Ionic Bonds from Formula 1)Write name of metal 2)Write name of non-metal 3)Non-metal suffix = IDE sodiumsodium chlorinesodium chloride NaCl

Cations and Anions Common Simple Cations and Anions CationName AnionName* H 1+ hydrogen H 1- hydride Li 1+ lithium F 1- fluoride Na 1+ sodium Cl 1- chloride K 1+ potassium Br 1- bromide Cs 1+ cesium I 1- iodide Be 2+ beryllium O 2- oxide Mg 2+ magnesium S 2- sulfide Al 3+ aluminum Ag 1+ silver * The root is given in color. Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 86

Writing Chemical Formulas for Ionic Compounds. Points to note: The metal ion/cation is always first The nonmetal ion/anion is always written second Steps: 1.Write the chemical symbols for each element (metal first) 2.Write the ionic charge above each element 3.Criss-cross the NUMBERS (not the signs) and write them as subscripts

Example: Aluminum Chloride Step 1: Step 2: Step 3: 13 Step 4: AlCl 3 Formula from Name: Criss-Cross Rule Al Cl write out name with space write symbols & charge of elements criss-cross charges as subsrcipts combine as formula unit (“1” is never shown) Aluminum Chloride

Example: Aluminum Oxide Step 1: Step 2: Step 3: 23 Step 4: Al O 3 Criss-Cross Rule Al O write out name with space write symbols & charge of elements criss-cross charges as subsrcipts combine as formula unit Aluminum Oxide 2

Example: Magnesium Oxide Step 1: Step 2: Step 3: 22 Step 4: Mg 2 O 2 Criss-Cross Rule Mg O Magnesium Oxide Step 5: MgO (reduce subscripts to lowest ratio)

Ex. 1 Magnesium and Chlorine Total Charge Check: Ex.2 Calcium and Oxygen Total Charge Check:

HINTS: Criss-cross rule will help you to figure out the right subscript in the compound formula Ignore subscript if it is 1 Subscripts do not have signs: it’s a number of ions! Final formula shall not indicate charge on top Reduce subscripts, go by lower terms

Naming Binary Compounds FormulaName 1 BaO____________________ 2________________ sodium bromide 3 MgI 2 ____________________ 4 KCl____________________ 5________________ strontium fluoride 6________________ cesium fluoride barium oxide NaBr magnesium iodide potassium chloride SrF 2 CsF

Multivalent Binary Compounds Containing a Metal (Variable Oxidation Number) and Non Metal To name these compounds (stock system): 1.Write the name of the metal 2.Followed by Roman numerals in parentheses to indicate the oxidation number of the metal 3.Write the name of the nonmetal, with its ending replaced by the suffix –ide. ExamplesIUPAC System FeCl 2 Iron (II) chloride SnOTin (II) oxide FeCl 3 Iron (III) chloride SnO 2 Tin (IV) oxide

Common Multivalent Cations IonIUPAC System Fe 3+ iron (III) Fe 2+ iron (II) Cu 2+ copper (II) Cu 1+ copper (I) Au 3+ gold (III) Au 1+ gold (I) Sn 4+ tin (IV) Sn 2+ tin (II) Pb 4+ lead (IV) Pb 2+ lead (II) Cr 3+ chromium (III) Cr 2+ chromium (II) Ni 3+ Nickel (III) Ni 2+ Nickel (II) Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 90

Naming Binary Compounds FormulaName 1 SnF 4 ____________________ 2 HgO____________________ 3________________ copper (II) fluoride 4________________ copper (I) sulfide 5 Cr 2 O 3 ____________________ 6________________ lead (IV) oxide tin (IV) fluoride PbO 2 mercury (II) oxide CuF 2 Cu 2 S chromium (III) oxide