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Classifying Binary Compounds. Binary ionic compounds contain a metal and a nonmetal. 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
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Classifying Binary Compounds • Binary ionic compounds contain a metal and a nonmetal. • 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 • Charge determined by position on the Periodic Table (group 1A: +1; group 2A: +2) • Type II • Metals that can have more than one possible charge (transition metals) • Metal cation’s charge (usually +1, +2, +3, or +4) determined from the charge on anion
Type I Binary Ionic Compounds • Contain Metal Cation from Groups 1A, 2A or Al, Ga, & In (metals with only one possible ionic charge) + Nonmetal Anion • Metal listed first in formula & name • Name metal cation first, name nonmetal anion second • Nonmetal anion named by changing the ending on the nonmetal name to –ide
Name the following Type I Compounds: You must know the simple cations and anions in Table 5.1 • MgCl2 • K2O • CaBr2 • BaS
Type II Binary Ionic Compounds • 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 • Nonmetal anion named by changing the ending on the nonmetal name to -ide
Determining the Charge on a Cation – Au2S3 • Determine the charge on the anion • Au2S3: the anion is S, since it is in Group 6A, and its charge is –2 • Determine the total negative charge • Since there are 3 S in the formula, the total negative charge is –6 • Determine the total positive charge • Since the total negative charge is -6, the total positive charge is +6 • Divide by the number of cations • Since there are 2 Au in the formula & the total positive charge is +6, each Au has a +3 charge
Name the following Type II compounds: • CrCl3 • CrCl2 • Cu2O • CuO • Fe2S3
Type III - Binary Compounds of Two Nonmetals • 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! • Use a prefix in front of each name to indicate the number of atoms. • Never use the prefix mono- on the first element.
Subscript Prefix 1 mono- (not used on first nonmetal) 2 di- 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa- Prefixes • Drop last “a” in the prefix if the name begins with vowel: N2O5 dinitrogen pentoxide (not pentaoxide)
Name the following Type III compounds: • CCl4 • N2O3 • PCl3 • PCl5 • CO
Classify and name the following binary compounds: • OCl2 • CaBr2 • CuS • B2O3
Compounds Containing Polyatomic Ions • Polyatomic ions are charged entities that contain more than one atom (e.g. HSO4-) • Must memorize name, formula, and charge • Table 5.4 • Polyatomic compounds contain one or more polyatomic ions. • To name these compounds you must learn to recognize the polyatomic ions. (NH4C2H3O2) ammonium acetate
Compounds Containing Polyatomic Ions (cont.) • Name polyatomic compounds by naming cation and anion. • Non-polyatomic ions named like Type I and II Na2SO4 sodium sulfate • Polyatomic acids contain H+ and a polyatomic anion.
Oxyanions • -ate ion • chlorate = ClO3- • -ate ion plus 1 O same charge, per- prefix • perchlorate = ClO4- • -ate ion minus 1 O same charge, -ite suffix • chlorite = ClO2- • -ate ion minus 2 O same charge, hypo-prefix, -ite suffix • hypochlorite = ClO-
Patterns for Polyatomic Ions • Elements in the same column on the periodic table form similar polyatomic ions. • Same number of O’s and same charge ClO3- = chlorate BrO3- = bromate • If the polyatomic ion starts with H, add hydrogen- before the ion’s name and add one to the charge. CO32- = carbonate HCO3- = hydrogen carbonate
Name the following compounds: • Na3PO4 • FeCO3 • (NH4)2CO3 • Ca(CN)2
Naming Acids • Formulas always begin with H as first element • Can be thought of as consisting of H+ cation and anion • Binary acids have H+ cation and a nonmetal anion • Oxyacids have H+ cation and a polyatomic anion
Naming Acids (cont) • If the anion does not contain oxygen, use the prefix hydro- plus the suffix –ic attached to the root name of the element followed by the word acid. • HBr: • When the anion contains oxygen, use the root name of the central element of the anion, with a suffix –ic or –ous, followed by the word acid. When the anion name ends in -ate, the suffix –ic is used. When it ends in –ite, the suffix –ous is used. • H2SO4: • H2SO3: • HNO3: • HNO2:
Writing Formulas from Names • For Type I, Type II, polyatomic compounds and acids: • Determine the ions present. • Determine the charges on the cation and anion. • Balance the charges to get the subscripts. • For Type III compounds, use the prefixes to determine the subscripts.
Write the formula for each of the following compounds: • diboron trioxide • copper(III) bromide • chromium (II) permanganate • phosphorus tribromide