Naming Compounds Handout PDF

Naming Compounds Handout IONIC COMPOUNDS versus MOLECULAR COMPOUNDS ionic compound: consist of cations (positive ions) and anions (negative ions) held together by electrostatic attraction – usually metal + nonmetal(s)...

Naming Compounds Handout IONIC COMPOUNDS versus MOLECULAR COMPOUNDS ionic compound: consist of cations (positive ions) and anions (negative ions) held together by electrostatic attraction – usually metal + nonmetal(s) – made of monatomic ions, polyatomic ions, and/or both – monatomic ions: consist of a single atom – polyatomic ions: consist of more than one atom molecular compound: consist of nonmetal atoms bonded together by shared electrons (covalent bonding) – acid: a molecular compound that releases + hydrogen ions (H ) when dissolved in water NAMING MONATOMIC CATIONS: Metal atoms lose valence electrons to form positively charged ions, called cations. An ion formed from an individual atom is a monatomic (or monoatomic) cation. I. Groups IA to IIIA elements silver (Ag), zinc (Zn) and cadmium (Cd) form only one type of ion each: + + + + + – Group IA elements form +1 ions: Li , Na , K , Rb , Cs +2 +2 +2 +2 +2 – Group IIA elements form +2 ions: Be , Mg , Ca , Sr , Ba +3 – Group IIIA elements form +3 ions: Al + +2 +2 – silver ion = Ag ; zinc ion = Zn ; cadmium ion = Cd When a Group IA–IIIA element, silver, zinc, or cadmium forms an ion, it is named: element name + ion + +2 +2 e.g. Na = sodium ion Sr = strontium ion Zn = zinc ion CHEMISTRY Naming Compounds Handout page 1 of 12  II. The Stock system is used to name transition metals and other metals that form more than one ion: +2 +3 – iron (Fe) forms two ions: Fe and Fe +2 +4 – lead (Pb) forms two ions: Pb and Pb When a a metal can form more than one ion, each ion is named: element name (charge in Roman numerals) + ion +2 +2 + e.g. Fe = iron (II) ion Pb = lead (II) ion Cu = copper (I) ion +3 +4 +2 Fe = iron (III) ion Pb = lead (IV) ion Cu = copper (II) ion Name each of the following monatomic cations: + +2 Li = _________________________ Cd = _________________________ + +2 Ag = _________________________ Cu = _________________________ +3 +2 Al = ________________________ Mg = _________________________ +2 +4 Mn = ________________________ Sn = _________________________ + +3 H = _________________________ Co = _________________________ +3 + Fe = ________________________ Na = _________________________ + +4 K = ________________________ Ti = _________________________ +2 +2 Ca = ________________________ Ni = _________________________ CHEMISTRY Naming Compounds Handout page 2 of 12 NAMING MONATOMIC ANIONS: Nonmetal atoms gain valence electrons to form negatively charged ions called anions. When a nonmetal forms an ion, it is named: element stem name + “ide” + ion –2 e.g. O = oxygen atom ⇒ O = oxide ion –3 N = nitrogen atom ⇒ N = nitride ion Name each of the following monatomic anions: – – F = _________________________ Cl = _________________________ – –2 Br = _________________________ S = _________________________ – –3 I = _________________________ P = _________________________ NAMING POLYATOMIC IONS: Ions made up of more than one atom are polyatomic ions: + – only one polyatomic cation: NH4 = ammonium ion – many polyatomic anions: see table below NH4+= ammonium ion Polyatomic Ions – – – OH = hydroxide ion NO2 = nitrite ion C2H3O2 = acetate ion – – –3 CN = cyanide ion NO3 = nitrate ion PO4 = phosphate ion –2 –2 – CrO4 = chromate ion SO4 = sulfate ion MnO4 = permanganate ion –2 –2 –2 Cr2O7 = dichromate ion SO3 = sulfite ion CO3 = carbonate ion – HCO3 = hydrogen carbonate ion or bicarbonate ion CHEMISTRY Naming Compounds Handout page 3 of 12 Name each of the following polyatomic ions: – –2 CN = _________________________ CrO4 = _______________________ –2 – SO4 = _________________________ NO3 = ________________________ – –3 OH = _________________________ PO 4 = ________________________ + – NH 4 = _________________________ C 2H3O 2 = _____________________ WRITING CHEMICAL FORMULAS GIVEN INDIVIDUAL IONS Compounds must be neutral ⇒ total +ve charge = total –ve charge 1. If the two ions have exactly opposite charges (+1 and –1, +2 and –2, +3 and –3) fi formula of the compound contains one of each ion + – + – e.g. Na + Cl ⇒ NaCl K + NO3 ⇒ KNO3 +2 –2 +2 –2 Ca + S ⇒ CaS Ba + SO4 ⇒ BaSO4 +3 –3 +3 –3 Al + N ⇒ AlN Fe + PO4 ⇒ FePO4 Combine each pair of ions to get the formula of the compound they form: + – + – NH4 + F ⇒ ________________ Li + CN ⇒ ________________ +2 –2 +3 –3 Sr + CO3 ⇒ ________________ Al + PO4 ⇒ ________________ + – + – Na + C2 H 3 O 2 ⇒ ________________ K + OH ⇒ ________________ +2 –2 +3 –3 Ni + CrO4 ⇒ ________________ Fe + N ⇒ ________________ +2 –2 +3 –3 Cd + SO4 ⇒ ________________ Co + P ⇒ ________________ CHEMISTRY Naming Compounds Handout page 4 of 12  2a. If two monatomic ions have different charges ⇒ use crossover rule to get formula of the compound – superscript for cation becomes subscript for anion – superscript for anion becomes subscript for cation – simplify subscripts to get lowest ratio of atoms (Note: Only the numbers cross down, not the signs!) Na+ S 2– > Ba2+ N3– > > Ti 4+ O> > 2– Na2S Ba3N2 TiO2 Ti2O4 is simplified! b. If two ions have different charges and at least polyatomic ion is involved ⇒ use crossover rule to get formula of the compound – if more than one of polyatomic ion in formula, use parentheses – simplify subscripts to get lowest ratio of atoms (Note: Again only the numbers cross down, not the signs!) 2+ NH+4 O2– – > Ca NO3> Pb>4+ CO2– 3> (NH4)2O Ca(NO3)2 Pb(CO3)2 Pb2(CO3)4 is simplified! Combine each pair of ions to get the formula of the compound they form: + –2 +4 –2 + –3 Cu O Sn SO4 K P + –2 +3 –2 +2 –3 Li CO3 Fe S Ni PO4 CHEMISTRY Naming Compounds Handout page 5 of 12 CHEMICAL FORMULAS AND NAMES FROM INDIVIDUAL IONS Compounds are named from the individual ions they come from. Name the cation and the anion, then remove “ion” from each name: + e.g. Na = sodium ion – Cl = chloride ion ⇒ NaCl = sodium chloride + K = potassium ion –2 CO3 = carbonate ion ⇒ K2CO3 = potassium carbonate +3 Fe = iron (III) ion – NO3 = nitrate ion ⇒ Fe(NO3)3 = iron (III) nitrate + Ag = silver ion –2 S = sulfide ion ⇒ Ag2S = silver sulfide Combine each pair of ions to get the chemical formula, then name the compound: Individual ions Compound Formula Compound Name +2 – Mg F _____MgF2______ ______magnesium fluoride_____ +2 –2 Ni S _______________ ___________________________ +2 – Ca Br _______________ ___________________________ +3 –3 Al P _______________ ___________________________ +2 – Co NO2 _______________ ___________________________ + –2 K CrO4 _______________ ___________________________ +3 –2 Fe O _______________ ___________________________ CHEMISTRY Naming Compounds Handout page 6 of 12 GIVEN THE CHEMICAL FORMULA, NAME THE COMPOUND 1. If the metal is in Groups IA–IIIA, silver, cadmium, or zinc, then just name the metal cation and the anion: e.g. NaCl ⇒ Na = sodium and Cl = chloride ⇒ sodium chloride BaI2 ⇒ Ba = barium and I = iodide ⇒ barium iodide Al(OH)3 ⇒ Al = aluminum and OH = hydroxide ⇒ aluminum hydroxide ZnSO4 ⇒ Zn = zinc and SO4 = sulfate ⇒ zinc sulfate 2. If the metal can form more than one ion, a. Use reverse crossover to get the individual ions – Make the subscript of cation the negative charge of anion – Make the subscript of anion the positive charge of cation b. Check to make sure the charges on the ions are correct c. Name the cation and the anion, then remove “ion” from both +2 – e.g. Ni Br2 ⇒ Ni = nickel (II) ion Br = bromide ion Is bromide’s charge really –1? YES! then ⇒ NiBr2 = nickel (II) bromide d. If a polyatomic ion is involved, remember that more than one polyatomic is shown in parentheses—i.e. DO NOT bring up the subscript of atoms in a polyatomic ion to be the charge of the metal! CuSO4 ⇒ There is only ONE Cu and ONE SO4, so get the charge –2 for the Cu based on the SO4. The formula is SO4 , and –2 there is only ONE SO4 , so Cu’s charge here must be +2 for the compound to have an overall charge of zero. ⇒ Cu+2 = copper (II) ion SO4 = sulfate ion –2 then ⇒ CuSO4 = copper (II) sulfate CHEMISTRY Naming Compounds Handout page 7 of 12 Give the name for each compound given its chemical formula: Formula Individual Ions Name of Compound +2 MgCl2 Mg Cl– magnesium chloride LiOH ZnCO3 K2S FePO4 SnO2 CuBr2 Ag3N Mn(CN)2 AgC2H3O2 WRITING CHEMICAL FORMULAS GIVEN THE COMPOUND NAME Get the individual ions from the name, then combine them using the crossover rule: +2 – e.g. barium chloride ⇒ barium = Ba chloride = Cl Ba+2 Cl– ⇒ BaCl2 +3 –2 aluminum sulfate ⇒ aluminum = Al sulfate = SO4 Al+3 SO4–2 ⇒ Al2(SO4)3 CHEMISTRY Naming Compounds Handout page 8 of 12 Give the name for each compound given its chemical formula: Name of Compound individual ions Formula + – lithium cyanide Li CN LiCN iron (III) sulfate calcium iodide tin (IV) dichromate cadmium nitrite copper (II) acetate zinc carbonate lead (II) phosphide potassium sulfite cobalt (II) nitride nickel (II) permanganate NAMING MOLECULAR COMPOUNDS Indicate number of atoms of each element with Greek prefix before element name: # of atoms Greek Prefix # of atoms Greek Prefix 1 mono (usually omitted) 6 hexa 2 di 7 hepta 3 tri 8 octa 4 tetra 9 nona 5 penta 10 deca CHEMISTRY Naming Compounds Handout page 9 of 12  For the first element: Greek prefix + element name For the second element: Greek prefix + element name stem + “-ide” Note: Mono is generally omitted, except in common names like CO = carbon monoxide P2O5 SF6 diphosphorus pentaoxide sulfur hexafluoride Name the following molecular compounds: SO3 = _____________________ SiBr4 = ______________________ XeF6 = ______________________ ClF3 = ______________________ N2O4 = ______________________ Cl2O7= ______________________ PCl5 = ______________________ P4O10 = _____________________ DETERMINING FORMULAS OF MOLECULAR COMPOUNDS Use Greek prefix(es) to determine number of atoms of each element in formula. Get elements and number of atoms of each from name: tetraphosphorus hexasulfide P4S6 CHEMISTRY Naming Compounds Handout page 10 of 12 Give the formulas for each of the following molecular compounds: nitrogen trichloride dibromine heptaoxide dinitrogen pentasulfide DETERMINING FORMULAS AND NAMES OF ACIDS FROM IONS Given an ion, we can get formula of acid by: adding H atoms equal to negative charge on ion we can name for acid: depending on suffix of ion name add # of H's equal – to negative charge F = fluoride ion HF (aq) = hydrofluoric acid add # of H's equal – to negative charge NO2 = nitrite ion HNO2 (aq) = nitrous acid add # of H's equal –2 to negative charge SO4 = sulfate ion H2SO4 (aq) = sulfuric acid Name each of the following ions, and determine the formula and name of the corresponding acid that forms from the ion. Name of Ion Formula of Acid Name of Acid – Cl = _____chloride ion_____ ⇒ ____HCl____ (aq) = ___hydrochloric acid____ –2 CO3 = _________________ ⇒ _________ (aq) = _______________________ –2 SO3 = _________________ ⇒ _________ (aq) = _______________________ –3 PO4 = _________________ ⇒ _________ (aq) = _______________________ – NO3 = __________________ ⇒ __________ (aq) = ______________________ CHEMISTRY Naming Compounds Handout page 11 of 12  Name each of the following acids: HBr (aq)= _________________ H2CrO4 (aq)= ___________________ H2SO4 (aq)= _______________ HC2H3O2 (aq)= ________________ Give the formula for each of the following acids: [Don’t forget to indicate (aq)!] hydrofluoric acid = __________ nitrous acid = ___________ phosphoric acid = ___________ chromic acid = ___________ hydroiodic acid = ___________ carbonic acid = ___________ sulfurous acid = ___________ nitric acid = ___________ PUTTING IT ALL TOGETHER: Name each of the following compounds: BaCl2 _____________________ NiBr2 ____________________ HNO3(aq)_____________________ SO2 ____________________ AgF _____________________ PbSe2 ____________________ NiSO3 _____________________ PF5 ____________________ K2SO4 _____________________ Cr(C2H3O2)3________________ FeP _____________________ Al2(CO3)3 ___________________ CuMnO4 _____________________ Cd(OH)2 __________________ CHEMISTRY Naming Compounds Handout page 12 of 12