Naming ionic-covalent
- 1. Naming Compounds What's in a name? That which we call a rose By any other name would smell as sweet." - William Shakespeare, Romeo and Juliet (II, ii)
- 2. Background: valences and formulas • We can determine the formula of a compound by completing Lewis diagrams or via “valence” • Valence is “the number of electrons an atom must gain, lose, or share to complete its octet” • For representative elements valence starts at 1 (1), climbs to 4 (4) and falls back to 1 (7) • By knowing the valence of elements you can determine the formula of compounds • E.g. what compound would form from C + S? Step 1 - write valences: C 4S 2 Step 2 - cross down valences: C2S4 Step 3 - simplify formula: CS2
- 3. Ionic compounds (metal with 1 valence) Rules for naming • Names end in -ide. Example: sodium chloride • Metal (+ ion) comes 1st (not chlorine sodide) • Use the group valence for nonmetals • Do not capitalize the compound unless starting a sentence Give formulae & name: Ca + I, O + Mg, Na + S = Ca2I1 = CaI2 = calcium iodide = Mg2O2 = MgO = magnesium oxide = Na1S2 = Na2S = sodium sulfide
- 4. Write the correct formula for these a) Al + Br AlBr3 b) K+S K2 S c) Zn + O ZnO d) Mg + N Mg3N2 e) C + Cl CCl4 f) Cu + O CuO or Cu2O
- 5. Learning Check Complete the names of the following binary compounds: Na3N sodium ________________ KBr potassium ________________ Al2O3 aluminum ________________ MgS _________________________
- 6. Multiple valence: Latin naming • When the metal in an ionic compound is multi- valent there are 2 methods: Latin or IUPAC • Latin is older (not useful for some compounds) • As before, the name ends in -ide & + is first • The metal is named with it’s Latin or English root and ends in -ic or –ous to denote valence • E.g. Cu1 is cuprous, E.g. Cu2 is cupric • Lower = ous, Higher = ic (lower & higher charge) • Give formulas and Latin names for: Cu2 + Cl = Cu2Cl1 = CuCl2 = cupric chloride Co2 + Cl = Co2Cl1 = CoCl2 = cobaltous chloride For latin naming: know rules, remember Hg is an exception, do not memorize Latin names
- 7. Element English Latin Name Higher Lower (valence) name valence valence Metals that have and use latin names Cu (1,2) Copper Cuprum Cupric Cuprous Fe (2,3) Iron Ferrum Ferric Ferrous Pb (2,4) Lead Plumbum Plumbic Plumbous Sn (2,4) Tin Stannum Stannic Stannous Metals that do not have latin names Co (2,3) Cobalt - Cobaltic Cobaltous Cr (2,3) Chromium - Chromic Chromous Mn (2,3) Manganese - Manganic Manganous Metals that have latin names but use english root Hg (1,2) Mercury Hydrargyrum Mercuric Mercurous
- 8. Multiple valence: IUPAC naming • Name ends in -ide, positive/metal comes first • The valence (charge) of the metal is indicated in brackets using roman numerals • E.g. Cu1 is copper(I), Cu2 is copper(II) • Numbers refer to charge not to #s of atoms
- 9. Write the correct name and formula • Cu2+Cl • Zn2 + Cl • Co2+Cl • Hg+S (do both) a) Cu2+Cl = Cu2Cl1 = CuCl2 = copper(II)chloride b) Zn2+Cl = Zn2Cl1 = ZnCl2 = zinc chloride c) Co2+Cl = Co2Cl1 = CoCl2 = cobalt(II) chloride d) Hg+S = Hg1S2 = Hg2S = mercury(I) sulfide d) Hg+S = Hg2S2 = HgS = mercury(II) sulfide
- 10. Learning Check Complete the names of the following binary compounds with variable metal ions: FeBr2 iron (_____) bromide CuCl copper (_____) chloride SnO2 ___(_____ ) ______________ Fe2O3 ________________________ Hg2S ________________________
- 11. Compounds containing polyatomic ions • So far we have given valences to single atoms Li1O2 → Li2O • Groups of atoms can also have valences Li + O • “Polyatomic ions” are groups of atoms that interact as a single unit. • E.g. OH1, (SO4)2. • Ba3(PO4)2 = barium phosphate • Naming compounds with polyatomic ions is similar to naming other ionic compounds • You should note that compounds with polyatomic ions have names ending in -ate or -ite not -ide • Note that most are negative, except ammonium
- 12. Naming with Transition Metals Name Balanced Ion Formula Pairs Lead (IV) Hydroxide Iron (III) Carbonate Copper (II) acetate
- 13. Naming with Transition Metals Name Balanced Ion Formula Pairs Lead (IV) Pb+4 + 4(OH-) Hydroxide Iron (III) 2Fe+3 + 3CO3-2 Carbonate Copper (II) Cu+2 + 2C2H302-1 acetate
- 14. Naming with Transition Metals Name Balanced Ion Formula Pairs Lead (IV) Pb+4 + 4(OH-) Pb(OH)4 Hydroxide Iron (III) 2Fe+3 + 3CO3-2 Fe2(CO3)3 Carbonate Copper (II) Cu+2 + 2C2H302-1 Cu(C2H302)2 acetate
- 15. Write the name • Ca(OH)2 • Cu(SO4) • NH4(NO3) • Co2(CO3)3 a) Calcium hydroxide b) Copper (II) sulfate c) Ammonium nitrate d) Cobalt (III) carbonate
- 16. Naming covalent compounds 1 mon • -ide ending, each element has o • prefix refers to # of atoms - not valence “prefix” 2 di N2O4 = dinitrogen tetroxide 3 tri • Exception: drop mono for first element 4 tetra CO2 = carbon dioxide 5 pent • The first vowel is often dropped to 6 a hexa avoid the combination of “ao” or “oo”. 7 hept CO = carbon monoxide P4O10= tetraphosphorus decoxide (monooxide) 8 a octa SO2= sulfur dioxide (doxide) 9 nona • Name: CCl4, P2O3, IF7 1 deca
- 17. Write and name the following covalent compounds (IUPAC) CCl4 carbon tetrachloride P2O3 diphosporus trioxide IF7 For more lessons, visit www.chalkbored.com