J OURNAL #56 Give the names for the following compounds: CuCl2 CoI2 HgI2 PbS2 Write the formula and give the name for the compound formed between the ions: Cu + and O 2- Fe 3+ and O 2-

T ODAY WE WILL GIVE THE NAMES FOR POLYATOMIC I ONS

C OMMON P OLYATOMIC I ONS Most are negatively charged and are oxyanions. Oxyanions - polyatomic ions that contain Oxygen Some elements combine to form more than one type of oxyanion Example: nitrogen can form NO 3 - and NO 2 -

C OMMON P OLYATOMIC I ONS The name given a compound containing such an oxyanion depends on the number of oxygen atoms in the oxyanion. The name of the ion with the greater number of oxygen atoms ends in –ate. The name of the ion with the smaller number of oxygen atoms ends in –ite. Examples: NO 3 - and NO 2 -  Nitrate Nitrite

Sometimes an element can form more than 2 types of oxyanions. The anion that has one fewer oxygen atom that the –ite anion has a given prefix hypo- An anion that has more than one oxygen atom than the –ate anion has is given the prefix per- Example: ClO - ClO 2 - ClO 3 - ClO 4 - Hypochlorite ChloriteChloratePerchlorate

C OMPOUNDS CONTAINING P OLYATOMIC I ONS Named the same was as binary ionic compounds The name of the cation is given first, followed by the name of the anion. Example: silver nitrate, AgNO 3 Example: Silver nitrite, AgNO 3

C OMPOUNDS CONTAINING P OLYATOMIC I ONS When multiples of polyatomic ion are present in a compound, the fomrular for the polyatomic ion is enclosed in parenthesis. Example: Al 2 (SO 4 ) 3 The aluminum sulfate formula unit has 2 aluminum cations and 3 sulfate anions

W RITE THE FORMULA FOR TIN (IV) SULFATE. 1. Write the symbols for each ions side by side. Write the cation first 2. Cross over the charges to give subscripts. Add parentheses around the polyatomic ion if necessary. Sn 2 (SO 4 ) 4  Sn(SO 4 ) 2

W RITE THE FORMULA FOR SODIUM CARBONATE 1. Write the symbols for each ions side by side. Write the cation first 2. Cross over the charges to give subscripts. Add parentheses around the polyatomic ion if necessary. Na 2 CO 3