Chapter 6. Language of Chemistry

Nomenclature Chapter 6: Language of Chemistry (Nomenclature)  We will be presenting this chapter a bit different than the text book does. The information is the same, so reading the text is still a good idea. But take a careful look at the online notes for this chapter.  Check the nomenclature handout on my website (next to the Ch. 6 label – left side)  PRACTICE, PRACTICE, PRACTICE Terms and Definitions Naming Flowchart  Ionic compound = metal + nonmetals Is the compound ionic, covalent, or acid?  Covalent compound = nonmetals only, (aka molecular)  Monoatomic ion = one atom w/charge  Na+, Cl-, Ca2+ Ionic: metal + nonmetal Is the metal a transition metal?  Polyatomic ion = two or more atoms w/charge (listed on your Periodic Table – become familiar with them)  PO43-, OH-, CO32- Use Roman numerals to identify the charge on the metal (except Ag+, Zn2+, Cd2+) Covalent/Molecular Compounds  Compounds with only nonmetals  These are neutral compounds that do NOT have a charge.  Use prefixes • mono (1)  penta (5)  hexa (6) • di (2)  hepta (7) • tri (3) • tetra (4)  octa (8)  Prefix + 1st nonmetal; prefix + 2nd nonmetal + “ide” Don’t use mono- if there’s only 1 of the 1st element Is the nonmetal a polyatomic ion? Covalent: 2 or more Acid: nonmetals H…(aq) Use prefixes to identify how many of each element. HCl(aq) HBr(aq) HF(aq) HNO3(aq) H2CO3(aq) H2SO4(aq) Examples  CO2 is carbon dioxide Name the following:  CO  P2 O 5  PF3  IF7  H2O 1 Practice Covalent/Molecular Naming Element Names  Know the names for elements 1-20 AND  Br3O8  P4S7 Iron: Fe Cobalt: Co Nickel: Ni Copper: Cu Zinc: Zn Bromine: Br Strontium: Sr  SO3  iodine hexafluoride  dichlorine pentaoxide  P2I4 Ionic Compounds  We’ll start by learning charges of ions and how to write formulas for ionic compounds.  Remember that ionic compounds are made of ions, and ions have a charge.  The sum of the charges must equal zero. Silver: Ag Tin: Sn Iodine: I Barium: Ba Gold: Au Mercury: Hg Lead: Pb Oxidation States  Oxidations states are determined similar to charges of ions.  All elements have a charge of zero when they are alone (elemental state - ex: Zn(s), H2(g), Br2(l))  Elements have a charge only have they react and lose or gain electrons!  Some elements have a fixed charge – only one possibility (e.g., Na+, Cl-, etc.)  Other elements have variable charge – several possibilities (e.g., Fe 2+ and Fe3+) Metal Cations (+) Nonmetal Anions (-)  Metals lose electrons to become cations (+)  Nonmetals gain electrons to become anions (-)  Charges (learn these)  Charges (learn these) • • • • • • Column IA is always +1 (alkali metals) Column IIA is always +2 (alkaline earth metals) Column IIIA is often +3 (Al3+ always) Zn and Cd always +2 Silver always +1 Other metals can vary from +1 to +9 so use Roman Numeral to tell the difference; Cu+2 is copper(II), Fe+3 is iron(III), Pb+4 is lead(IV) • • • • Column 5 is usually –3 Column 6 is usually –2 Column 7 is usually –1 (F always) Column 8 is 0 Why??? • Noble gases are already happy with 8 outer valence electrons (He has 2 v. e.), so they don’t need to form bonds. They don’t easily gain or lose electrons!!! 2 6.3 Polyatomic Ions  Check out information on your periodic table – lower left corner.  Keep these atoms together as a group, think of them as a group, a single unit.  LEARN THESE. Be familiar with them (formulas and names).  Examples: CO32-, SO42-, PO43-, OH- Formulas of Ionic Compounds  Compounds MUST be neutral  Need enough cations and anions to have an overall zero charge  Combine Na and N  Na is +1; N is –3 so we need three Na’s for one N  Na3N is the formula  Practice: Write the formula for ions of Rb and S.  Start by writing the charge of each ion. Formulas of Ionic Compounds What will the formulas be when the following ions are combined? • Na and S • Mg and O • K and Br • Ca and N • Al and Cl • Zn and I • Cu(II) and O • Pb(IV) and O Naming Ionic Compounds  Now that we can write ionic compound formulas, we can name them.  Naming the cation (metal) depends on whether it has a fixed or variable charge.  Naming the anion (nonmetal) depends on whether it is a single atom ion or polyatomic ion.  Metal + nonmetal (NO prefixes: the charges on ions determines how many we need.) Formulas with Polyatomic Ions What will the formulas be when the following ions are combined? • Mg and OH• K and PO43• Ag and SO42• Ca and NO3• Cu(II) and CO32- Ionic Compounds: Fixed Charge Cation  For a fixed charge metal, like Na, it can only have one possible charge so we don’t use Roman numerals  Metal name + nonmetal-“ide” • NaCl sodium chloride • Name the following: • KBr • MgO • CaF2 • Li2S • AgCl 3 Ionic Compounds: Variable Charge Cation  For a variable charge metal, like Cu, the charge can vary so we do use Roman numerals  Metal (Roman #) + nonmetal-“ide”  YOU must figure out charge on transition metal • Name CuCl2 • Name the following: • • • • • PbO2 FeBr3 CoS HgBr CoN Ionic Compounds: Review  YOU must be able to figure out the formula AND the name for ionic compounds.  Example: K and O • What is the correct formula? • What is the correct name?  You need to practice writing formulas from names and names from formulas; this applies to covalent and ionic compounds. Naming Acids  Compounds that lower pH in water by producing H+ ions. Ionic Compounds: Polyatomic Ions  Do NOT change the polyatomic ion name • NaNO3 • Name the following: • K3PO4 • Ca(OH)2 • ZnSO4 Ionic Compounds: Review  Prefixes are ONLY with covalent compounds  Roman Numerals are ONLY with variable charged metal compounds (in ionic compounds)  Transition metals (except Zn2+, Cd2+, Ag+)  Main group metals (except Pb2+/4+, Sn2+/4+)  Polyatomic ions NEVER change their name OR CHARGE What does (aq) mean?  Acids are always dissolved in water = (aq)  You need to know these 6 acids: • • • • • • HCl(aq) HF(aq) H2SO4 (aq) H3PO4 (aq) HNO3 (aq) H2CO3 (aq) hydrochloric acid hydrofluoric acid sulfuric acid phosphoric acid nitric acid carbonic acid 4 Nomenclature Practice: 3 minutes! Ch. 6 Self Test, p. 187  BaCl2 Try 3, 4, 6, 9, 11  NO2 Answers in Appendix J  Fe3(PO4)2  diiodine tetraoxide  silver sulfate  nickel(III) sulfide •Do the chapter 6 worksheet posted on my and Dr. Kim’s web pages •Seriously – JUST DO IT 5