Ionic Compound Formulation & Nomenclature

• All ionic compounds consist of two parts: a cation (a positive ion) and an anion (a negative ion). • Ions are combined in simple, whole-number ratios to balance their charges. This results in a net charge of zero, which all ionic compounds MUST have. • The “cross technique” is used to create the correct ratio of ions needed. Example: aluminum (Al+3) and oxygen (O-2). Al O +3 -2 Al O +3 -2 Al O 2 3 2 3 1. Write the symbols, then write the charges on each symbol (from ion list) 2. Cross the charges, dropping the + and – symbols (don’t write 1s) 3. Clean up the formula (completely erase all charges) and reduce if necessary. So when do you need to reduce?

Ca O Ca O CaO Sn S Sn S SnS2 +2 -2 2 2 +4 -2 2 4 2 • Here’s two examples of when the ratio needs to be reduced: Ca O +2 -2 Ca O CaO 2 2 +4 -2 Sn S Sn S SnS2 2 4 2 • Let’s try formulating some compounds (putting them together):

Mg+2 F- Fe+3 Br- K+ Cl- Ca+2 Cl- Ag+ N-3 MONATOMIC • Let’s try formulating some compounds (putting them together): Let’s try naming some compounds: MONATOMIC magnesium fluoride = ______________ iron (III) bromide = ________________ potassium chloride = ______________ calcium chloride = ________________ silver nitride = ____________________ MgF2 FeBr3 KCl CaCl2 Ag3N tin (II) sulfide = ___________________ barium phosphide = _______________ cobalt (III) oxide = _________________ copper (I) iodide = _________________ lead (IV) selenide= ________________ Mg+2 F- Fe+3 Br- K+ Cl- FeO ___________________ Al2O3 __________________ K2O____________________ PbO2 __________________ K2S ___________________ Mn3P2 ___________________ Na2S____________________ Ag2S ____________________ Cu3N ____________________ ZnCl2 ___________________ Ca+2 Cl- Ag+ N-3

Sn+2 S-2 Ba+2 P-3 Co+3 O-2 Cu+ I- Pb+4 Se-2 MONATOMIC • Let’s try formulating some compounds (putting them together): Let’s try naming some compounds: MONATOMIC magnesium fluoride = ______________ iron (III) bromide = ________________ potassium chloride = ______________ calcium chloride = ________________ silver nitride = ____________________ MgF2 FeBr3 KCl CaCl2 Ag3N tin (II) sulfide = ___________________ barium phosphide = _______________ cobalt (III) oxide = _________________ copper (I) iodide = _________________ lead (IV) selenide= ________________ Sn2S2 Ba3P2 Co2O3 CuI Pb2Se4 SnS PbSe2 Sn+2 S-2 Ba+2 P-3 Co+3 O-2 FeO ___________________ Al2O3 __________________ K2O____________________ PbO2 __________________ K2S ___________________ Mn3P2 ___________________ Na2S____________________ Ag2S ____________________ Cu3N ____________________ ZnCl2 ___________________ Cu+ I- Pb+4 Se-2

Zn+2 = zinc Fe+2 = iron (II) Sc+3 = scandium Fe+3 = iron (III) • Ionic compounds are named with the following rules: • The cation name goes first, the anion name goes second. • cations are usually metals. The name of the cation does not change from the name of the element. • Note: If the element is polyionic (meaning it can have more than one type of charge), this must be indicated by placing a roman numeral after the name to indicate the size of the charge. • anions are a single negatively charged element (monatomic)—name of element with ending taken off and “-ide” added. Zn+2 = zinc Sc+3 = scandium Fe+2 = iron (II) Fe+3 = iron (III)

iron ( ) oxide aluminum oxide potassium oxide lead ( ) oxide • Let’s try formulating some compounds (putting them together): Let’s try naming some compounds: magnesium fluoride = ______________ iron (III) bromide = ________________ potassium chloride = ______________ calcium chloride = ________________ silver nitride = ____________________ MgF2 FeBr3 KCl CaCl2 Ag3N tin (II) sulfide = ___________________ barium phosphide = _______________ cobalt (III) oxide = _________________ copper (I) iodide = _________________ lead (IV) selenide= ________________ Sn2S2 Ba3P2 Co2O3 CuI Pb2Se4 SnS PbSe2 iron ( ) oxide aluminum oxide potassium oxide lead ( ) oxide potassium sulfide II IV manganese ( ) phosphide sodium sulfide silver sulfide copper ( ) nitride zinc chloride II I FeO ___________________ Al2O3 __________________ K2O____________________ PbO2 __________________ K2S ___________________ Mn3P2 ___________________ Na2S____________________ Ag2S ____________________ Cu3N ____________________ ZnCl2 ___________________

Covalent Bonding Characteristics and Nomenclature

Covalent compounds share electrons, (ionic bonds transfer them). Covalent bonds = two nonmetals, or a nonmetal and a metalloid. Remember, hydrogen is not an alkali metal, it is a nonmetal. Remember, ionic bonds always contain a metal. Metals never appear in covalent compounds!!! Covalent bonds rely on the “octet rule,” meaning that atoms in a covalent bond need 8 electrons around them (in most cases). covalent bonds can be single, double, or triple, in order to satisfy the octet rule. Lewis-dot structures show the arrangement of these eight electrons CF4 CO2 N2 4 single bonds 2 double bonds 1 triple bond F F C F O C O N N

covalent compounds can involve the same elements with multiple ratios (such as C3H8, C2H4, NO2, N2O), so the ratio in the compound must be shown in the name. to write the name of a covalent compound, we use Greek prefixes: attach the appropriate prefix to the name of each element in the compound. (Note: if the first element in the compound is single, you do not need the prefix “mono-.” “Mono-” is only used on the second element!) the ending of the second element’s name is taken off, and “-ide” is added. if you get any of the following vowel combinations in the name when you add the prefix: “oo,” “ao,” “oa,” or “aa,” that’s not allowed! Drop the vowel off of the prefix, and then add it to the name. for diatomic gases, like O2, name the element, then add the word “gas.” Therefore, O2 = oxygen gas # Prefix 1 mono- 2 di- 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa- 9 nona- 10 deca-

dicarbon hexanitride no AO combo! triphosphorus heptaoxide heptoxide Let’s try a few: C2N6 = _____________________ P3O7 = _____________________ H2O = ______________________ B5As = ______________________ N2 = _______________________ trisulfur tetrachloride = ___________ carbon monoxide = ___________ chlorine gas = ____________ silicon pentabromide = ___________ tetrachlorine decabromide = ___________ dicarbon hexanitride no AO combo! triphosphorus heptaoxide heptoxide no OO combo! dihydrogen monoxide monooxide no OA combo! pentaboron monoarsenide monarsenide nitrogen gas (diatomic gas!) S3 Cl4 C O Cl2 (diatomic gas!) Si Br5 Cl4 Br10

Place an “I” or a “C” in the blank: Can you tell the difference between an ionic compound and a covalent compound based on the name or formula alone? You need to be able to do so! Place an “I” or a “C” in the blank: Fe3N2 K2S NH3 Br2 Mn2O3 CaO Li2O ___ I ___ C carbon dioxide aluminum nitride tin (II) sulfide chlorine gas calcium sulfide cobalt (III) oxide sodium phosphide I I C I C C I I I I I I