Nomenclature Naming compounds Writing Formulas

Naming Compounds Binary Compounds Compounds that contain two elements Name the first element Name the second element using an “ide” ending Check the oxidation number of the first element If it has more than one positive value, use a Roman numeral to indicate the number that was used

CaCl 2 Calcium Calcium chloride Ca is +2 only No Roman numeral needed Calcium chloride

CCl 4 Carbon Carbon chloride C is -4, +2 and +4 Since there are two positive choices, use a Roman numeral C Cl 4 Carbon IV chloride -4+4 =0

Naming Compounds Ternary Compounds Compounds that contain more than two elements Polyatomic ion is present Two or more elements that join together and act like one substance Found on Table E Identify the polyatomic used Name the first substance Name the second substance Check the oxidation number of the first element If it has more than one positive value, use a Roman numeral to indicate the number that was used

K 2 SO 4 Potassium Potassium sulfate Potassium is +1 only No Roman numeral is needed Potassium sulfate

Cu(NO 3 ) 2 Copper Copper nitrate Copper can be +1 or +2 Needs a Roman numeral Cu (NO 3 ) 2 -2=0 +2 Copper II nitrate

NH 4 Cl Ammonium Ammonium chloride Ammonium ion is +1 No choice means no Roman numeral needed Ammonium chloride

Prefix System Use a prefix INSTEAD OF a Roman numeral Mono 1only used for the 2 nd element Di 2 elements Tri 3 elements Tetra 4 elements CO 2 Carbon dioxide

Suffix System Used INSTEAD OF a Roman numeral “-ic Highest oxidation state “-ous” Lowest positive oxidation state NiCl 2 Nickel II chloride Nickelous chloride

B. Writing Formulas Use ending to tell if compound is binary or ternary Binary usually ends in “ide” [except hydroxide and cyanide] Ternary usually ends in “ate” or “ite” Write the symbols Assign oxidation numbers Positive atom on left, negative on right Reduce if possible and “criss-cross” These numbers become the subscripts of the formula

Strontium phosphide “ide” means binary Strontium (Sr) Phosphide is phosphorus (P) Sr +2 P -3 Sr 3 P 2

Iron II Oxide “ide” means binary Iron (Fe) Oxide is oxygen (O) Fe +2 O -2 Fe 2 O 2 reduce FeO

Manganese IV Carbonate “ate” means ternary Manganese (Mn) Carbonate is a polyatomic ion (CO 3 -2 ) Mn +4 CO 3 -2 Mn 2 (CO 3 ) 4 reduce Mn (CO 3 ) 2

Ferrous sulfide ferr- represents Fe (iron) -ous represents lowest positive state sulfide represents sulfur Fe +2 S -2 Fe 2 S 2 reduces to FeS

Diphosphorus trioxide NO CHARGES ASSIGNED NO CRISS-CROSSING Diphosphorus P2P2 Trioxide O3O3 Formula P2O3P2O3