Naming Compounds Having Polyatomic Ions Objective: To learn the names of common polyatomic ions and how to use them in naming compounds.
Define polyatomic ion A group of atoms with a charge Some Examples SO42- CN- C2H3O2- sulfate cyanide acetate OH- NO3- NO2- Hydroxide nitrate nitrite
Polyatomic vs. Monatomic How are the ions S2- and SO42- different? SO42- is five atoms combined to make one ion. SO43- is a polyatomic ion
Turn to page 100 Note the table listing the most common polyatomic ions. This table will be supplied to you when you take the test. Let’s look at it.
What do you notice about the names of most polyatomic ions? Most end with either –ite or –ate. Notice there are some that end in -ide.
Perchlorate ClO4- chlorate ClO3- chlorite ClO2- hypochlorite ClO- Chloride Cl-
Naming Compounds that Contain Polyatomic Ions Say the name of the positive ion Say the name of the negative ion Na2SO3 K2SO4 sodium sulfite potassium sulfate KC2H3O2 Potassium acetate
This will be easier if you remember this: Compounds only have two names CuCO3 Copper(II) carbonate
Compounds Containing SO42- The name of the polyatomic ion is sulfate BaSO4 Al2(SO4)3 barium sulfate aluminum sulfate CaSO4 Na2SO4 calcium sulfate sodium sulfate
Compounds Containing OH- The name of the polyatomic ion is hydroxide NaOH Cu(OH)2 sodium hydroxide copper(II) hydroxide Al(OH)3 Fe(OH)2 aluminum hydroxide Iron(II) hydroxide
Compounds Containing C2H3O2- Ba(C2H3O2)2 Cu(C2H3O2)2 Barium acetate copper(II) acetate Mg (C2H3O2)2 Hg2(C2H3O2)2 Magnesium acetate mercury(I) acetate
Compounds Containing H2PO4- The name of the polyatomic ion is dihydrogen phosphate. NaH2PO4 Remember: Say the name of the positive ion and then the name of the negative ion. Sodium dihydrogen phosphate
Writing Formulas of Compounds that Contain Polyatomic Ions Sodium phosphate
Write the Formula for Barium Nitrate
Write the Formula for Calcium Hydroxide
Write the Formula for Calcium chloride Only put parentheses around polyatomic ions
Write the formula for ammonium carbonate