Naming Ions and Writing Formulas for Ionic Compounds

Monoatomic ions single atom with a charge Cation - + charge from losing e- Anion - - charge from gaining e- Cations are the name of the element. For example: Na+ sodium ion Mg2+ magnesium ion Anions change the ending to –ide. For example: O2- oxide Cl- chloride

Polyatomic ions composed of more than one atom -1 Charge Acetate CH3COO- or C2H3O2- Nitrite NO2- Nitrate NO3- Cyanide CN- Hydroxide OH- Hypochlorite ClO- Chlorite ClO2- Chlorate ClO3- Perchlorate ClO4- -2 Charge Sulfite SO32- Sulfate SO42- Carbonate CO32- -3 Charge Phosphate PO43- +1 Charge Ammonium NH4+

NAMING/WRITING BINARY IONIC COMPOUNDS Binary – compound made of two kinds of elements Examples: NaCl, MgBr2, FeI3

Writing the formulas Cation (+) first Anion (-) last “criss-cross” method Naming the formulas Examples: NaCl sodium chloride MgBr2 magnesium bromide FeI3 iron iodide

NAMING/WRITING COMPOUNDS WITH POLYATOMIC IONS Writing the formulas Cation (+) first Anion (-) last “criss-cross” method Naming the formulas Examples: NH4Cl ammonium chloride Ca(OH)2 calcium hydroxide Na2SO4 sodium sulfate

Stock System using Roman numerals in nomenclature Used for transition metals with more than one possible charge (there are others) FOR EXAMPLE: FeCl2 and FeCl3 are both iron chloride. To differentiate, use the stock system: FeCl2 = iron (II) chloride FeCl3 = iron (III) chloride

Hinge Questions: Write the names for these formulas. CaI2 NiO Al2S3