Naming Ionic Compounds Ionic Nomenclature Naming Ionic Compounds

Ionic Compounds Review Ionic compounds are made of positive and negative ions. Also known as “salts”. Polyatomic ions are groups of atoms that behave as a single ion: Examples: CO3-2 CN-1 SO4-2

Naming Ionic Compounds Two types of ionic compounds: Binary, contains 2 elements NaCl, MgBr2, Fe2O3 Ternary, contains 3 elements Two of the elements are in a polyatomic ion NaNO3, NH4Cl, Cr2(SO4)3

Naming Binary Ionic Compounds Some metal ions have only one possible charge: Group 1A metal ions all have +1 charge. Group 2A metal ions all have +2 charge. Ag+1, Zn+2, Cd+2, Al+3, Ga+3 For fixed charge cations, name as element. Na+1 = sodium ion Ca+2 = calcium ion Ag+1 = silver ion Ga+3 = gallium ion Name anion as stem of element’s name followed by suffix –ide. Cl-1 = chloride ion S-2 = sulfide ion N-3 = nitride ion

Fixed Charge Metal Ions Be+2 Na+1 Mg+2 Al+3 K+1 Ca+2 Zn+2 Ga+3 Rb+1 Sr+2 Ag+1 Cd+2 Cs+1 Ba+2 Fr+1 Ra+2

Naming Binary Ionic Compounds NaCl KBr MgF2 CaO AgI Al2S3 Zn3P2 sodium chloride potassium bromide magnesium fluoride calcium oxide silver iodide aluminum sulfide zinc phosphide

Naming Binary Ionic Compounds Most metals can form multiple cations. Iron can form Fe+2 ions or Fe+3 ions. Copper can form Cu+1 ions or Cu+2 ions. For variable charge cations, name as element w/ Roman numeral in ( ) to indicate charge. Fe+2 = iron(II) ion Fe+3 = iron(III) ion Cu+1 = copper(I) ion Cu+2 = copper(II) ion Pb+2 = lead(II) ion Pb+4 = lead(IV) ion

Variable Charge Metal Ions

Naming Binary Ionic Compounds The compound must be electrically neutral. Use the charge of the anion to figure out the charge of the metal. Example: Fe2O3 (2 x Fe) + (3 x -2) = neutral (2 x Fe) – 6 = neutral (2 x Fe) = +6 Fe = +3 iron(III) oxide Example: FeO Fe + -2 = neutral Fe = +2 iron(II) oxide

Naming Binary Ionic Compounds FeCl2 Fe2Se3 CuBr CuS CrO CrI3 PbF2 PbS2 iron(II) chloride iron(III) selenide copper(I) bromide copper(II) sulfide chromium(II) oxide chromium(III) iodide lead(II) fluoride lead(IV) sulfide

Naming Ternary Ionic Compounds Name metal as you would for a binary, with charge as a Roman numeral if necessary. Name polyatomic anions as themselves. Know these: CO3-2 = carbonate NO3-1 = nitrate PO4-3 = phosphate SO4-2 = sulfate OH-1 = hydroxide ClO-1 = hypochlorite ClO3-1 = chlorate C2H3O2-1 = acetate CH3COO-1 = acetate CN-1 = cyanide

Naming Ternary Ionic Compounds Only one polyatomic cation: NH4+1 = ammonium Name it, then name the anion properly.

Naming Ternary Ionic Compounds LiNO3 Mg(OH)2 Fe2(SO4)3 Zn(C2H3O2)2 AlPO4 NH4Cl Cr(CN)2 lithium nitrate magnesium hydroxide iron(III) sulfate zinc acetate aluminum phosphate ammonium chloride chromium(II) cyanide

Writing Formulas From Names To write an ionic formula from a name, write the ions with their proper charges, then criss-cross. Don’t forget that polyatomic ions need parentheses if there’s more than one of them. Write the formula for iron(III) hydroxide iron(III) = Fe+3 hydroxide = OH-1 iron(III) hydroxide  Fe+3 + OH-1  Fe(OH)3 Write the formula for potassium sulfate potassium = K+1 sulfate = SO4-2 potassium sulfate  K+1 + SO4-2  K2SO4

Writing Formulas From Names calcium carbonate  sodium oxide  aluminum cyanide  potassium acetate  copper(II) hydroxide  gold(III) sulfide  Ca+2 + CO3-2  Na+ + O-2  Al+3 + CN-1  K+1 + C2H3O2-1  Cu+2 + OH-1  Au+3 + S-2  CaCO3 Na2O Al(CN)3 KC2H3O2 Cu(OH)2 Au2S3