210 likes | 320 Views
Nomenclature Chapter 5. Common Names - Exceptions. H 2 O = water, steam, ice NH 3 = ammonia CH 4 = methane NaCl = table salt C 12 H 22 O 11 = table sugar. Naming Starts with Classifying Compounds. Binary Compounds = only 2 elements Compounds containing polyatomic ions
E N D
Common Names - Exceptions • H2O = water, steam, ice • NH3 = ammonia • CH4 = methane • NaCl = table salt • C12H22O11 = table sugar
Naming Starts with Classifying Compounds • Binary Compounds = only 2 elements • Compounds containing polyatomic ions • Acids = formula often starts with H
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
Binary Ionic • Made of metal cation and nonmetal anion • Name by naming the ions
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 from the charge on anion
Type I Binary Ionic Compounds • Contain Metal Cation + Nonmetal Anion • Metal listed first in formula & name • Name metal cation first, name nonmetal anion second • Simple metal cation name is the metal name • simple metals are Groups 1A, 2A and Al, Ga & In • Nonmetal anion named by changing the ending on the nonmetal name to -ide
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 • 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, 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
Type III - Binary Compounds of 2 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
Compounds Containing Polyatomic Ions • Polyatomic ions are charged entities that contain more than one atom • Must memorize name, formula and charge • Look for Patterns!! • Polyatomic compounds contain one or more polyatomic ions • Name polyatomic compounds by naming cation and anion • Non-polyatomic ions named like Type I and II • Polyatomic Acids contain H+ and a polyatomic anion
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 ions name and add 1 to the charge CO32- = carbonate HCO3- = hydrogen carbonate
Patterns for Polyatomic Ions • -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-
Acids • Contain H+ cation and anion • Binary acids have H+ cation and a nonmetal anion • Oxyacids have H+ cation and a polyatomic anion
Writing the Formulas from the Names • For Type III compounds, use the prefixes to determine the subscripts • 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