Naming Chemical Compounds 1

Ions: Naming and Formulas Cations (positive charge) Single ion formation – Metals in groups 1,2,13 – Element Name + ion – ex. Ca +2  Calcium ion Multiple ion formation - Transition metals, Tin and Lead - Element Name (RN) + ion - Roman Numeral (RN) = charge - ex. Fe +3  Iron (III) ion Anions (negative charge) Nonmetals – Root of Element –ide – ex. S -2  sulfide Formulas -- element symbol AND charge Charge is determined by group number or roman numeral Naming : 2

Naming Binary Compounds – 2 Elements Cation/1 st element = name of element (always 1 st ) Anion/2 nd element = root of element + ide – Type I (Ionic) – cation only forms a single ion…. Nothing added – Type II (Ionic) - cation forms multiple ions….. roman numeral must be added (between cation and anion names) to indicate charge of the metal – Type III (covalent) – 1 st element is a nonmetal … Prefixes are used to indicate number of atoms for 1 st and 2 nd element Mono- never used on 1 st element 3

Type I (binary ionic) Characteristics – 2 elements – Metal + Nonmetal – Metal found in groups 1,2,13,Zn +2,Ag +,Cd +2 Rules – cation (+) named 1 st, anion (-) named second – cation  element name – anion  root of element name + (-ide) * subscripts of chemical formulas are NOT indicated directly in compound name 4

Type II (binary ionic) Characteristics – 2 elements – Metal + Nonmetal – Metal found in groups 3-12,Pb,Sn Rules – cation (+) named 1 st, anion (-) named second – cation  element name (roman numeral) roman numeral indicates the charge of the cation – anion  root of element name + (-ide) *subscripts of chemical formulas are NOT indicated directly in compound name 5

Determining Charge for Roman Numerals Total charge of + ions and – ions = 0 (# +ions)(charge +ions) + (# -ions)(charge –ions) = 0 Example: FeCl (1) Fe ion + (2 Cl)(-1) = 0 Fe ion + (-2) = 0 Fe ion = 2+ Cr 2 O (2) Cr ion + (3 O) (-2) = 0 2 Cr ions + (- 6) = 0 2 Cr ions = 6+ Cr ion = 3+ = Cr 3+ 6

Type III (binary covalent) Characteristics – 2 elements – Nonmetal + Nonmetal Rules – 1 st element  element name – 2 nd element  root of element name + (-ide) – Use prefixes on both elements to indicate the number of atoms (subscripts) 1 (mono) 2 (di) 3 (tri) 4 (tetra) 5 (penta) 6 (hexa) 7 (hepta) 8 (octa) 9 (nona) 10 (deca) NEVER use (mono) on the 1 st element No double vowels with “o” and “a” 7

Non-binary Ionic Characteristics – 3 or more elements – contains a polyatomic ion Rules – Cation Metal (groups 1,2,13,Zn +2,Ag +,Cd +2 )  element name Metal (groups 3-12, Pb, Sn)  element name ( roman numeral ) Polyatomic ion  name on reference sheet – Anion Nonmetal  root of element name + (-ide) Polyatomic ion  name on reference sheet 8

Writing Formulas Elements and Compounds 9

Element Formulas Monatomic Elements – Only the element symbol is used for the formula Diatomic Elements – These elements can NOT exist in nature as single atoms, they must be paired. – They include: hydrogen (H 2 ), nitrogen (N 2 ), oxygen (O 2 ), fluorine (F 2 ), chlorine (Cl 2 ), bromine (Br 2 ), and iodine (I 2 ). 10

Compound Formulas - Ionic Ionic (metal and nonmetal) – Symbol Elements – symbol on periodic table Polyatomic ions – reference sheet – Charges Group charges – 1(+1), 2(+2), 13(+3), 15(-3), 16(-2), 17(-1) Roman numerals – charge of the transition metal Polyatomic ions – reference sheet – Switch total (+) = total (-) Charge #’s cross down to become the subscripts on the other element – Reduce Subscripts must be in smallest ratios 11

Compound Formulas – Covalent Covalent (only nonmetals) – Convert prefixes to subscripts – place BEHIND the element symbol Mono – 1 Di – 2 Tri – 3 Tetra – 4 Penta – 5 Hexa – 6 Hepta -7 Octa – 8 Nona – 9 Deca