Binary Ionic Compounds - Weebly

Polyatomic Ionic Compounds Definition Polyatomic Ion- more than one atom that together have a charge Polyatomic Ionic Compoundcompound containing at least one polyatomic ion + + Cation Cation Polyatomic Anion

Polyatomic Ionic Compound Common Polyatomics Name Symbol OH-1 Hydroxide NO3-1 Nitrate

ClO3-1 Chlorate CO3-2 Carbonate SO4-2 Sulfate PO4-3

Phosphate NO2-1 Nitrite SO3-1 Sulfite CN-1 Cyanide HCO3-1

Bicarbonate C2H3O2-1 Acetate ClO4-1 Perchlorate ClO2-1 Chlorite

ClO-1 Hypochlorite NH4+1 Ammonium Practice Identifying Polyatomic Ions Example: Identify and name the polyatomic ion in each

compound NaNO3 NH4Cl Ca(OH)2 (NH4)3PO4 K2CO3 Note: Parenthesis are only used on POLYs and only when we need more than one. You cant change the subscript on the poly. Example - Al2(SO4)3 Three SO4-2 groups NOT SO43-2 Practice Identifying Polyatomic Ions Example:

Identify and name the polyatomic ion in each compound NaNO3 Nitrate NH4Cl Ammonium Ca(OH)2

Hydroxide (NH4)3PO4 Ammonium & phosphate K2CO3 Carbonate Naming Polyatomic Ionic Compounds To name these compounds:

Write the name of the cation If it is a metal just name the metal If it is a multivalent metal, name the metal and put a set of parenthesis after it If it is a NH4 write down the name ammonium Name the anion If the anion is a polyatomic ion, just name the polyatomic If the anion is a single non-metal element, write its name with the suffix -ide Determine the roman numeral if it is multivalent Example #1 NaNO3

Example #1 Sodium Cation NaNO3 Polyatomic Anion Nitrate Sodium Nitrate Example #2

K2SO4 Example #2 Potassium Cation K2SO4 Polyatomic Anion sulfate Potassium sulfate Example #3

Cu(OH)2 Example #3 Copper A Multivalent Metal Cation Cu(OH)2 Polyatomic Anion Two OH-1 groups

provide a total charge of -2. The Copper has to be +2 to balance this charge. hydroxide Copper (II) hydroxide Example #4 (NH4)2S Example #4

Ammonium Polyatomic Cation (NH4)2S Anion sulfur becomes sulfide Ammonium sulfide Writing Formulas for Polyatomic

Ionic Get out your Poly List!!!! To write these formulas: Write the symbol & charge of the cation & anion Add additional cations or anions to have a neutral compound. (We once again do this by balancing charge. Methods such as the Swap/Drop/Reduce or Lowest Common Multiple) Use subscripts to show the number of ions When using subscripts with a polyatomic ion, you must put the polyatomic ion in parenthesis. Example #1

Sodium carbonate Example #1 Na+1 Cation Sodium carbonate Polyatomic Anion CO3-2 Example #1 Na+1

Cation Na+1CO32 Sodium carbonate Polyatomic Anion CO3-2 Na2CO3 - +1 + -2 = -1 Na+1Na+1CO32+1 + 1 + -2 = 0

The subscript 2 is used to show that 2 cations are needed. Example #2 Magnesium nitrate Example #2 Mg+2 Cation Magnesium nitrate Polyatomic

Anion NO3-1 Example #2 Mg+2 Mg+2NO3- Cation +2 + -1 =+ 1 Magnesium nitrate Mg+2NO3- NO3- Polyatomic

Anion +2 + -1 + -1 = 0 NO3-1 Mg(NO3)2 The subscript 2 is used to show that 2 anions are needed. Use parenthesis when adding subscripts to polyatomic ions