Nomenclature

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Nomenclature

• Chapter 4

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Nomenclature Naming

• Common names were created before there was a
  system in place
• More than 4 million chemical compounds,
  memorizing names would be impossible
• A system makes it much easier

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Binary Compounds

• Compounds composed of 2 elements
• 2 types
• Metal and Nonmetal
• Two Nonmetals

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4.1 Naming Compounds That Contain a Metal and a
Nonmetal

• Remember When metals and nonmetals combine the
  compound contains ions
• Resulting substance is a binary ionic compound
• Contain cation and anion in that order
• To name them simply name ions
• Cation is element name
• Anion is root of element name with ide at end
• NaCl is sodium chloride

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• Certain metal ions form only one cation
• Na is always Na
• Cs is always Cs
• Ca is always Ca2
• We will call these Type I cations and they form
  Type I binary compounds
• Other metal ions can form more than one cation
• Cr can form Cr2 or Cr3
• Lower oxidation number will end in ous
• Higher oxidation number will end in -ic
• We will call these Type II cations and they form
  Type II binary compounds

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Type I Binary Ionic Compounds

• Cation always named first, anion second
• When a single element is the cation we simply use
  its name
• When a single element is the anion take the root
  and add ide
• Examples
• NaI is sodium iodide
• CaO is calcium oxide
• What would KI be? Potassium iodide
• What would CsBr be? Cesium bromide
• Do Practice problems on page 87

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Type II Binary Ionic Compounds

• Need to specify which cation is used
• Is it Cr2 or Cr3?
• We will use Roman Numerals in name
• So if it is FeCl2 which Iron is it? Fe2 (the
  ferrous ion) or Fe3 (the ferric ion)?
• we know Chlorine has a 1- oxidation number so 2
  (1-) 2-, what must Fe be to cancel this out?
• Fe must be 2 so it is Fe2
• So name would be Iron II chloride
• Table 4.2 page 90

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4.2 Binary Compounds That Contain Only Nonmetals
(Type III)

• Write first element
• Write second element
• Add prefix to 1st element (but not mono-)
• Add prefix to 2nd element
• Why do we do this?
• NO, N2O5, and NO2 would all be nitrogen oxide
  under the normal rules
• Instead they are Nitrogen monoxide, Dinitrogen
  pentoxide, and Nitrogen dioxide

• one mono
• two - di
• three - tri
• four - tetra
• five - penta
• six - hexa
• seven - hepta
• eight - octa
• nine - nona
• ten - deca

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4.3 Review

• Type I
• metal and nonmetal
• Metal cation has only 1 oxidation number
• Type II
• Metal and nonmetal
• Metal cation has more than 1 oxidation number
• Tell which ox. it is with roman numerals
• Type III
• Nonmetal and nonmetal
• Use prefixes to name

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Naming Binary Compounds
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4.4 naming Compounds That Contain Polyatomic Ions

• FIRST Copy Table 4.4 on page 100 into notes
• Polyatomic ion a charged group of atoms bound
  together
• Oxyanion oxygen and another element
• Smallest hypo-
• Lower - -ite (If only 2, smallest)
• Higher - - ate (If only 2, largest)
• Largest hyper

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• When naming compounds with polyatomic ions follow
  same rules but anion (second part of formula) is
  a polyatomic ion just name it

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4.5 Naming Acids

• Acid produces H ions (protons) in water
• Tastes sour (not a good test)
• It is like a molecule with a H attached to an
  anion
• If no oxygen
• Hydro- in front, -ic at end
• HCl is Hydrochloric acid
• If oxygen
• Root of central element of anion or anion name
  with ic or ous
• Anion ends in ate then replace with ic
• Anion ends with ite then replace with -ous

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4.6 Writing Formulas From Names

• You know how to do this