09-Polyatomic ions

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					Naming Multivalent compounds Part II

     a. Back-Crossing

Ex        AuN


     b. Balancing Charges Method



Polyatomic Ions

Polyatomic ions are charged molecules. The atoms within a polyatomic ion are usually very
tightly bound together, so the ion retains its identity within ionic compounds and over the
course of many chemical reactions.

Because polyatomic ions are basic building blocks of so many ionic compounds, learning
the names, charges, and formulas of the most common polyatomic ions is absolutely

      o     A chart with a list of ions both monatomic and polyatomic can be found on this
            table below; each ion has a specific charge that is associated with the name it is
      o     Compounds formed with polyatomic ions must have balanced charge, just like
            those formed from monatomic ions
      o     This means that in many compounds there will be more than one unit of a given
            polyatomic ion
      o     This is reflected in the formulas of these compounds by the use of parentheses
      o     The subscript after the parentheses tells you how many units of that ion you have

                    Ion Formula                  Ion Name
                    NH4+1                        ammonium
                    ClO3-1                       chlorate
                    OH-1                         Hydroxide
                    NO3-1                        Nitrate
                    MnO4-1                       permanganate
                    CO3-2                        Carbonate
                    HCO3-1                       Bicarbonate
                    SO4-2                        Sulphate
                    HSO4-1                       Bisulfate
                    PO4-3                        phosphate
                    CN-1                         cyanide


NaOH                                  Fe(CO3)2                             Iron (II) sulfate

1. Name the following chemicals.

   a. Be(OH)2 _________________________________________
   b. MgSO4 __________________________________________
   c. Be(NO3)2 __________________________________________
   d. LiCN ______________________________________________
   e. NaHCO3 ____________________________________________
   f.   FeCO3 ______________________________________________
   g. Cu(OH)2 ___________________________________________
   h. CaCO3 _____________________________________________
   i.   Fe(CN)2 ___________________________________________
   j.   Sn(MnO4)2___________________________________________
   k. Ca3(PO4)2 ____________________________________________
   l.   Cu(ClO3)2 _____________________________________________
   m. Co(OH)2 ______________________________________________

2. Write the formula for the following compounds

   a. sodium nitrate __________________________________________
   b. calcium carbonate __________________________________________
   c. lithium sulfate __________________________________________
   d. beryllium phosphate __________________________________________
   e. magnesium hydroxide _________________________________________
   f.   sodium phosphate __________________________________________
   g. aluminum carbonate __________________________________________
   h. calcium chloride __________________________________________
   i.   sodium cyanide __________________________________________
   j.   aluminum oxide __________________________________________
   k. calcium phosphate _________________________________________
   l.   potassium permanganate ____________________________________
   m. ammonium chloride _________________________________________
   n. aluminum carbonate ________________________________________
   o. lithium chlorate        __________________________________________
   p. nickel(II) sulphate _____________________________________________
   q. manganese(II) nitrate __________________________________________
   r.   tin(II) bicarbonate    ___________________________________________

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