Naming CompoundsNaming Compounds

What's in a name? That which we call a roseBy any other name would smell as sweet."

- William Shakespeare, Romeo and Juliet (II, ii)

• 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: C4S2

Step 2 - cross down valences: C2S4

Background: valences and formulas

Step 3 - simplify formula: CS2

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

a) Al + Br b) K + Sc) Zn + O d) Mg + N e) C + Clf) Cu + O

Write the correct formula for these

AlBr3

K2SZnOMg3N2

CCl4CuO or Cu2O

Learning Check

Complete the names of the following binary compounds:

Na3N sodium ________________

KBr potassium ________________

Al2O3 aluminum ________________

MgS _________________________

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 = Co2 + Cl = Co2Cl1 = CoCl2 =

For latin naming: know rules, remember Hg is an exception, do not memorize Latin names

cupric chloridecobaltous chloride

Element(valence)

Englishname

Latin Name Highervalence

Lowervalence

Metals that have and use latin namesCu (1,2) Copper Cuprum Cupric CuprousFe (2,3) Iron Ferrum Ferric FerrousPb (2,4) Lead Plumbum Plumbic PlumbousSn (2,4) Tin Stannum Stannic Stannous

Metals that do not have latin namesCo (2,3) Cobalt - Cobaltic CobaltousCr (2,3) Chromium - Chromic ChromousMn (2,3) Manganese - Manganic Manganous

Metals that have latin names but use english rootHg (1,2) Mercury Hydrargyrum Mercuric Mercurous

• 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

Multiple valence: IUPAC naming

a) Cu2+Cl b) Zn2 + Cl c) Co2+Cld) 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

Write the correct name and formula

Learning Check

Complete the names of the following binary

compounds with variable metal ions:

FeBr2 iron (_____) bromide

CuCl copper (_____) chloride

SnO2 ___(_____ ) ______________

Fe2O3 ________________________

Hg2S ________________________

• Groups of atoms can also have valences• “Polyatomic ions” are groups of atoms that interact as a single unit. • E.g. OH1, (SO4)2. • Ba3(PO4)2 =

Compounds containing polyatomic ions• So far we have given valences to single atoms

Li + O Li1O2 Li2O

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

Naming with Transition Metals

Name Balanced Ion Pairs

Formula

Lead (IV) Hydroxide

Iron (III) Carbonate

Copper (II) acetate

Naming with Transition Metals

Name Balanced Ion Pairs

Formula

Lead (IV) Hydroxide

Pb+4 + 4(OH-)

Iron (III) Carbonate

2Fe+3 + 3CO3-2

Copper (II) acetate

Cu+2 + 2C2H302

-1

Naming with Transition Metals

Name Balanced Ion Pairs

Formula

Lead (IV) Hydroxide

Pb+4 + 4(OH-) Pb(OH)4

Iron (III) Carbonate

2Fe+3 + 3CO3-2 Fe2(CO3)3

Copper (II) acetate

Cu+2 + 2C2H302

-1 Cu(C2H302)2

Write the name

a) Ca(OH)2

b) Cu(SO4)

c) NH4(NO3)

d) Co2(CO3)3

a) Calcium hydroxideb) Copper (II) sulfatec) Ammonium nitrated) Cobalt (III) carbonate

Naming covalent compounds• -ide ending, each element has “prefix”1 mono

2 di

3 tri

4 tetra

5 penta

6 hexa

7 hepta

8 octa

9 nona

10 deca

• prefix refers to # of atoms - not valenceN2O4 = dinitrogen tetroxide

• Exception: drop mono for first elementCO2 = carbon dioxide

• The first vowel is often dropped to avoid the combination of “ao” or “oo”.

CO = carbon monoxide

(monooxide)SO2= sulfur dioxide (doxide)

• Name: CCl4, P2O3, IF7

P4O10= tetraphosphorus decoxide

Write and name the following covalent compounds (IUPAC)

carbon tetrachloride

diphosporus trioxide

iodine heptafluoride

CCl4

P2O3

IF7

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