Naming/writing ionic compounds

• Naming ionic compounds-

  Binary compounds

  • metals have have same name (Sodium), non metals will end in -ide but have the root of the name (Sulfide)

  example of a combined binary term without polyanides: MgS —> Magnesium Sulfide
• Naming binary ionic compounds with multiple charged metals (d block, f block, and group 14 because we don’t know their ion charges) involves using Roman numerals after the metal to indicate the charge of the metal.
• The final result is that chromium III is represented as the ionic charge and oxygen is changed to oxide, as it is a non-metal.
• Naming ternary ionic compounds

  Same rules as binary ionic

  • except look up the name of the polyatomic ion, on the ion sheet given, and write the name as it appear. Example: the picture‘s underlined polyatomic is the exact name with no changes. Na is not changed because it’s a metal So its sodium.

  
• Summary of writing ionic compounds-

  Identify the ending of the compound

  • -ide, if it’s not cyanide or Hydroxide then it’s a binary ionic compound, if not it’s ternary ionic compound
  • -ate, or -ite is ternary ionic compound
• Summary is naming ionic compounds-

  Identify the number of elements

  • 2 elements, then it’s a binary ionic : metal + non-metal -ide
  • 3 or more elements, then it’s a ternary ionic: name the metal + polyion OR name the polyion + non-metal -ide OR name the polyion + polyion
• in the case of this formula, we don’t know the charge of chromium because it’s in d block. So, we take the charge from oxygen which is 2- and multiply it by the amount of oxygen which is 3 and we get 6-. Since oxygen is 6- Chromium has to be 6+ so they cancel out. So we divide 6 by 2 and get 3 for chromium. We write this formula by first writing chromium because it’s a metal causing the name to stay the same and putting it in roman numerals (III) to represent the charge. then we chnage Oxygen to oxide since it’s a non metal. (This is the box method)