Nomenclature Chapter 5

Classifying Binary Compounds Compounds containing a metal and a nonmetal are binary ionic –Type I and II Compounds containing two nonmetals –Type III Compounds containing H and a nonmetal = Acids

Metal Cations Type I –Metals that can only have one possible charge –Determine charge by position on the Periodic Table Type II –Metals that can have more than one possible charge –Determine metal cation’s charge using the charge on anion

Type II Binary Ionic Compounds Contain Metal Cation + Nonmetal Anion Metal listed first in formula & name Name metal cation first, name nonmetal anion second Metal cation name is the metal name followed by a Roman Numeral in parentheses to indicate its charge –Determine charge from anion charge –Common Type II cations in Table 5.2 (page 128 or on Week #2 Ions & Symbols List) Nonmetal anion named by changing the ending on the nonmetal name to -ide

Writing Formulas for Binary Type II Compounds Cu +1 and N -3 Hg +2 and O -2 Cr +3 and P -3 Sn +4 and Cl -1 Ni +4 and S -2 Iron (III) phosphide Manganous fluoride Gold (I) telluride Plumbic bromide Cobalt (III) arsenide

Ionic Compounds Sometimes you can use the reverse of the criss-cross method to determine the charges for the transition metals. When naming compounds, you do not need to tell how many atoms of each ion are present.

Naming Binary Type II Compounds Au 2 S MnO Fe 3 N 2 CuCl 2 NiS 2 Cr 3 P 2 PbF 4 HgI

Type III - Binary Compounds of 2 Nonmetals These binary compounds always start with a nonmetal or a metalloid. That’s the easiest way to identify them. They will contain no metals! Name first element in formula first, use the full name of the element Name the second element in the formula as if it were an anion –However, remember these compounds do not contain ions, so DO NOT USE THE CRISS-CROSS METHOD!!!

Type III Binary Molecular Compounds Use a prefix in front of each name to indicate the number of atoms Never use the prefix mono- on the first element but always put a prefix on the second element. Prefixes: 1-mono, 2-di, 3-tri, 4-tetra,5-penta, 6-hexa, 7-hepta, 8-octa, 9-nona, 10-deca, 11- undeca, 12-dodeca. To write the formula for binary molecular compounds, write the number next to the compound if there is a prefix, if not just write the symbol itself.

Binary Molecular Compounds Examples Naming Compounds SiF 2 C 3 Cl 9 S 4 I 7 P 5 O 10 Writing Formulas Nitrogen trichloride Triphosphorus pentoxide Hexasulfur monofluoride Diselenium pentabromide

Figure 5.1: A flow chart for naming binary compounds.

Ionic Compounds Ternary ionic compounds – contain atoms of three or more different elements, usually a polyatomic ion. Writing the formulas for ternary compounds is done in the same way as binary compounds. The polyatomic ions stays together though.

Ionic Compounds When you need more than one polyatomic ion in your formula, put parentheses around the ion, and how many of them you need outside the parentheses as a subscript. NEVER MOVE SUBSCRIPTS OF THE IONS, ONLY THE CHARGES!!!

Writing Formulas for Ternary Ionic Compound Examples Calcium hydrogen sulfate Sodium chlorate Magnesium hydroxide Potassium phosphate Aluminum acetate Tin (IV) chromate Nickel (II) dihydrogen phosphate Chromium (III) sulfate Copper (II) acetate Iron (II) permanganate

Ionic Compounds When naming ternary compounds, name the cation (first symbol in the formula unless it is ammonium, NH 4 +1 ) first, and then the rest of the formula, which will only have one name, unless it contains hydrogen.

Naming Ternary Ionic Compounds Ca(NO 3 ) 2 KClO 3 BaSO 3 AlPO 4 (NH 4 ) 3 BO 3 Ni 3 (PO 3 ) 4 Fe(CN) 2 Mn(HCO 3 ) 3 Au 2 CO 3 Cr 2 HPO 4

Naming Compounds Containing a metal with more than one possible charge and a Polyatomic ion Ni 3 (PO 3 ) 4 Fe(CN) 2 Mn(HCO 3 ) 3 Au 2 CO 3 Cr 2 HPO 4 CuOH Sn(SO 3 ) 2 Co 3 (BO 3 ) 2 Hg(C 2 H 3 O 2 ) 2

Acids Naming & Writing Formulas for Acids All acids begin with a hydrogen, and are neutral compounds. In all acids, the cation is the hydrogen ion, H +1. Anions change their endings when they become acids.

Acids -ide ions become hydro root ic acid Ex: chloride becomes hydrochloric acid -ate ions become root ic acid Ex: nitrate becomes nitric acid -ite ions become root ous acid Ex: chlorite becomes chlorous acid

Acids Naming & Formula Writing Examples Naming Acids H 3 PO 3 HI HCN H 2 C 4 H 4 O 6 Writing Formulas for Acids Sulfuric acid Hydroarsenic acid Perchloric acid Hypochlorous acid