Chemistry Ch. 9.2

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Chemistry Ch. 9.2

• Naming and Writing Formulas for Ionic Compounds

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Naming Binary Ionic Compounds

• Binary compounds are composed of two elements and
  can be either ionic or molecular.
• If you know the formula for a binary ionic
  compound, you can write its name.
• Place the cation name first, followed by the
  anion name.
• NaBr is sodium bromide. SrF2 is strontium
  flouride.

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• CuO is not just copper oxide. Copper can form
  1 and a 2 cations. The formula indicates a 1
  to 1 ratio. Since oxygen is always 2-, the
  correct name is copper(II) oxide.
• What is the formula for copper(I) oxide?
• Cu2O.

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Writing Formulas for Binary Ionic Compounds

• Easy. Write the symbol of the cation and then
  the anion. Add whatever subscripts are needed to
  balance the charges.
• Calcium bromide. Ca2. Br-.
• CaBr2
• Use the crisscross method, and then reduce to the
  lowest whole number ratio if necessary.

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Compounds with Polyatomic Ions

• Again easy. Write the symbol for the cation
  followed by the formula for the polyatomic ion,
  and then balance the charges. Use crisscross
  method.
• Ca2 (NO3)-
• Ca(NO3)2

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Naming Compounds with Polyatomic Ions

• First, figure out if the compound contains a
  polyatomic ion!
• If so, then to name the compound, simply state
  the cation first and then the anionthe same as
  for binary ionic compounds.
• NaClO is sodium hypochlorite.
• What is (NH4)2C2O4 ?