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Chapter 7 Nomenclature CHM130 GCC
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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 an especially careful look at the online notes for this chapter. Good luck!
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Terms Ionic compound = metal + nonmetals
Covalent compound = nonmetals only, (aka molecular) Monoatomic ion = one atom w/charge Na+, Cl-, Ca2+ Polyatomic ion = two or more atoms w/charge (listed on your Periodic Table – become familiar with them) PO43-, OH-, CO32-
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Element Names Know the names for elements 1-20 AND Barium Ba Silver Ag
Cobalt Co Gold Au Iodine I Zinc Zn Copper Cu Tin Sn Iron Fe Strontium Sr Lead Pb Nickel Ni Mercury Hg Bromine Br
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Ionic Compounds We will begin by learning formulas and names for ionic compounds Remember that ionic compounds are made of ions, and ions have a charge The sum of the charges must = zero
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Oxidation States Is a fancy name for charge
All elements have a charge of zero when they are alone (elemental state) Elements have a charge when they have lost or gained electrons Some elements have a fixed charge – only one possibility Other elements have variable charge – several possibilities
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Cations Metals lose electrons to be cations (+) Charges (learn these)
Column IA is always +1 (alkali metals) Column IIA is always +2 (alkaline earth metals) Column IIIA is often +3 (Al 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 like Cu+2 is copper(II), Fe+3 is iron(III), Pb+4 is lead(IV)
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Anions Nonmetals gain electrons to be anions (-) Charges (learn these)
Column 5 is –3 usually Column 6 is –2 usually Column 7 is –1 usually (F always) Column 8 is 0 Why??? Noble gases are already happy with 8 outer valence electrons (He has 2) so don’t need to form bonds – they don’t want to gain or lose electrons!!!
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7.3 Polyatomic Ions Check out information on your periodic table
Keep these atoms together as a group, think of them as a group, a single entity
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Formulas of Ionic Compounds
Compounds MUST be neutral Need enough cations and anions to = zero Combine Na and N: Na is +1 and N is –3 so need three Na’s for one N so Na3N is the formula What is the formula? Na and S Mg and O K and Br Ca and N Al and Cl Zn and I Cu(II) and O Na2S MgO KBr Ca3N2 AlCl3 ZnI2 CuO
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Formulas with Polyatomic Ions
What is the Formula? Mg and OH- K and PO43- Ag and SO42- Ca and NO3- Cu(II) and CO32- Pb(IV) and O Mg(OH)2 K3PO4 Ag2SO4 Ca(NO3)2 CuCO3 PbO2
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Naming Ionic Compounds
Now that you can write ionic compound formulas, we need to learn their names The name depends on whether the metal has a fixed or variable charge For a fixed charge metal, like Na, we KNOW the charge so don’t use Roman numerals For a variable charge metal, like Cu, we don’t know the charge so we do use Roman numerals Check it out…
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Fixed charge metal ionic compound
Metal name + nonmetal + “ide” NaCl sodium chloride What is the name? KBr MgO CaF2 Li2S AgCl Note the ionic name does NOT indicate how many atoms there are Potassium bromide Magnesium oxide Calcium fluoride Lithium sulfide Silver Chloride
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Names with Polyatomic Ions
Do NOT change the polyatomic ion name NaNO3 sodium nitrate What is the name? K3PO4 Ca(OH)2 ZnSO4 Potassium phosphate Calcium hydroxide Zinc sulfate
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Variable charge Metal Ionic Compound
Metal name (Roman #) + nonmetal + “ide” YOU must figure out charge on Trans metal CuCl2 copper(II) chloride (Cu must be +2 since Cl is –1 and there are two of them) What is the name? PbO2 FeBr3 CoSO4 HgNO3 CoN Lead(IV) oxide Iron(III) bromide Cobalt(II) sulfate Mercury(I) nitrate Cobalt(III) nitride
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YOU must figure out the formula AND the name for ionic compounds.
Name only for covalent compounds (Why? They don’t have ions so you can’t add to zero) Example: K and O You figure out formula: You figure out name: K2O Potassium oxide
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Covalent / Molecular Compounds
Compounds with only nonmetals These are NOT ions, so no charges Use prefixes mono -penta di -hexa tri -hepta tetra -octa Prefix + nonmetal name + prefix + 2nd nonmetal name + “ide” Don’t use mono for the 1st nonmetal
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Examples CO2 is carbon dioxide What is the name? CO P2O5 PF3 IF7
Carbon monoxide Diphosphorus pentoxide Phosphorus trifluoride Iodine heptafluoride
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Given the formula, write the name and vice versa
Br3O8 P4S7 SO3 Iodine hexafluoride Dichlorine pentaoxide P2I4 Tribromine octaoxide Tetraphosphorus heptasulfide Sulfur trioxide IF6 Cl2O5 Diphosphorus tetraiodide
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Reminders Prefixes are ONLY with covalent compounds
Roman Numerals are ONLY with variable charged metal compounds Polyatomic ions NEVER change their name
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Acids Compounds that lower pH in water Have H+ ions in them
Dissolved in water = (aq) You should memorize these 6 acids HCl(aq) hydrochloric acid HF(aq) hydrofluoric acid H2SO4 (aq) sulfuric acid H3PO4 (aq) phosphoric acid HNO3 (aq) nitric acid H2CO3 (aq) carbonic acid
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What the heck is (aq)?
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Write the formula or name for each – you have 3 minutes!
Barium chloride Nitrogen dioxide Iron(II) phosphate I2O4 Ag2SO4 Ni2S3 BaCl2 NO2 Fe3(PO4)2 Diiodine tetraoxide Silver sulfate Nickel(III) sulfide
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Do the chapter 7 worksheet posted on this practice problems web page
Seriously – JUST DO IT Self Test Page 196 Try 4, 6, 9, 11 Answers in Appendix J
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