Naming Ionic Compounds

Charges Elements will gain or lose electrons to have 8 valence electrons. (This is the octet rule) Group 1A  +1 Group 2A  +2 Group 3A  +3 Group 4A  N/A Group 5A  -3 Group 6A  -2 Group 7A  -1 Group 8A  STABLE The charges of monatomic ions, or ions containing only one atom, can be determined by referring to the periodic table

Ionic Compounds ion : atom or group of atoms that has a charge A monatomic ion is one element with a charge A polyatomic ion is more than one element with a charge Example: SO42- ionic compound: compound formed between a cation ( +) and an anion (-). usually between a metal and a nonmetal. also form between a polyatomic ion (like ammonium) and either a metal or nonmetal. TRANSFER valence electrons

Ions A cation An anion A monatomic ion is one element with a charge positive ion formed when an atom loses electrons. Example: Na+ An anion negative ion is formed when an atom gains electrons Example: Cl- A monatomic ion is one element with a charge A polyatomic ion is a group of covalently bonded atoms with a charge Example: SO42-

Formation of Ionic Compounds objects with opposite charges attract each other. ionic bond = the strong attractive force between ions of opposite charge Strongest type of bond!! the overall charge of the compound will be … ZERO!

Examples of Formula Writing Write the formula for the compound formed between calcium and nitrogen Step One: Write the symbols and charges of the ions formed Ca2+ N3- Step Two: Balance the charges so the total is ZERO You will need 3 Calcium’s and 2 Nitride’s Step Three: Write the Formula Use subscripts to show the number of each ion needed Ca3N2

More examples Write the formula between Mg and Br Mg+2 Br -1 MgBr2

More examples Write the formula for the compound formed between Ca and S Ca+2 S-2 CaS

Polyatomic Ions Polyatomic ions are groups of atoms that have a charge For example: SO4 -2 NO3 –1 ClO3 –1 NH4 +1

Polyatomic Ions You must use parentheses when using subscripts with a polyatomic ion Ex: Calcium nitrate Ca +2 NO3 -1 Ca(NO3)2

Formula writing with polyatomic Ions Write the formula between ammonium and sulfate NH4 +1 SO4 -2 (NH4)2 SO4

More examples Copper (II) and chlorine Silver and Nitrate Magnesium and sulfite Calcium and sulfur Potassium and oxygen Ammonium and phosphate Ammonium and chlorine CuCl2 AgNO3 MgSO3 CaS K2O (NH4)3PO4 NH4Cl

Multiple Charges! There are some elements that form multiple charges That roman numeral will tell you the charge! For example: Copper (II)  Cu +2

Multiple Charges to Remember Copper Iron Lead Tin Manganese Gold Cobalt +1 and +2 +2 and +3 +2 and +4 +2, +4, and +7 +1 and +3

Naming ionic compounds In naming ionic compounds, name the cation first, then the anion. Cation name does not change. If the cation can have more than one charge (mostly transition metals), use a Roman Numeral after the element name to indicate the charge Ex. Iron (II) for Fe2+ or Iron (III) for Fe3+ Monatomic anions: change the ending to -ide. (ex. Br -, Cl-, O2-) Polyatomic Ions: do not change the name (ex. SO42-, CO32-, PO43-

Examples NaCl MgSO4 CuSO3 K3PO4 Fe(NO3)2 Ca(ClO3)2 NH4NO2 Al(ClO)3 Sodium chloride Magnesium sulfate Copper (II) sulfite Potassium phosphate Iron (II) nitrate Calcium chlorate Ammonium nitrite Aluminum hypochlorite

More examples Lead (IV) Oxide Ammonium Permanganate Cobalt (II) chloride Calcium sulfide Lithium nitrate Sodium acetate Tin (II) chloride PbO2 NH4MnO4 CoCl2 CaS LiNO3 NaCH3COO SnCl2