Nomenclature

• Naming Starts with Classifying Compounds

  • Binary Compounds = only 2 elements
  • Compounds containing polyatomic ions
  • Acids = formula often starts with H
• Common Names - Exceptions

  • H2O = water, steam, ice
  • NH3 = ammonia
  • CH4 = methane
  • NaCl = table salt
  • C12H22O11 = table sugar
• 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
• 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
• HF = hydrofluoric acid
• HCl = hydrochloric acid
• HBr = hydrobromic acid
• HI = hydroiodic acid
• HCN = hydrocyanic acid
• H2S = hydrosulfuric acid
• HNO3 = nitric acid
• HNO2 = nitrous acid
• H2SO4 = sulfuric acid
• H2SO3 = sulfurous acid
• H3PO4 = phosphoric acid
• HC2H3O2 = acetic acid
• 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
• NH4+ = ammonium
• NO2- = nitrite
• NO3- = nitrate
• OH = hydroxide
• CN- = cyanide
• HSO4- = hydrogen sulfate
• ClO = hypochlorite
• ClO2- = chlorite
• ClO3- = chlorate
• ClO4- = perchlorate
• C2H3O2- = acetate
• MnO4- = permanganate