Nomenclature

• We can determine the formula of a compound by completing Lewis diagrams or via the criss cross method • By knowing the valence of elements you can determine the formula of compounds • E.g. what compound would form from Ca + S?

Step 1 - write valences: Ca 2+ S 2 Step 2 - cross down valences: Step 3 – reduce: Ca 2 S 2 CaS a) Al,Br b) K,S c) Zn,O d) Mg,N e) C,Cl f) Cu,O

AlBr

3

K

2

S ZnO Mg

3

N

2

CCl

4

CuO or Cu

2

O

Ionic compounds

Rules for naming • Names end in -ide. Example: sodium chloride • Metal (cation) comes 1st (not chlorine sodide) • Do not capitalize (unless it ’ s the start of a sentence) Give formulae & name: Ca + I, O + Mg, Na + S = Ca 2 I 1 = Mg 2 O 2 = CaI 2 = calcium iodide = MgO = magnesium oxide = Na 1 S 2 = Na 2 S = sodium sulfide

Multiple valence: Latin naming

• When the metal in an ionic compound is multivalent there are 2 methods: Latin (Common Name) or IUPAC (Stock Method) • As before, the name ends in -ide & metal is first • The metal is named with it’s Latin or English root and ends in

-ic

or

–ous

to denote valence.

– E.g. Cu 1 is cuprous, E.g. Cu 2 is cupric • L

o

wer =

o

us, H

i

gher =

i

c • Give formulas and Latin names for: Cu

2+

+ Cl = CuCl 2 = cupric chloride = copper (II) chloride (IUPAC) Cu

+

+ Cl = CuCl = cuprous chloride = copper (I) chloride

Element (valence) English name Latin Name Higher valence Lower valence Cu (1,2) Fe (2,3) Pb (2,4) Sn (2,4) Co (2,3) Cr (2,3) Mn (2,3) Metals that have and use latin names Copper Iron Lead Cobalt Chromium Manganese Cuprum Ferrum Plumbum Tin Stannum Stannic Metals that do not have latin names Cupric Ferric Plumbic Cobaltic Chromic Cuprous Ferrous Plumbous Stannous Cobaltous Chromous Manganic Manganous Metals that have latin names but use english root Hg (1,2) Mercury Hydrargyrum Mercuric Mercurous

Multiple valence: IUPAC naming

• Name ends in -ide, positive/metal comes first • The valence of the metal is indicated in brackets using roman numerals • E.g. Cu

1

is copper(I), Cu

2

is copper(II) • Numbers refer to valences not to #s of atoms • Try: • Cu

2

+Cl, Zn

2

+ Cl, Co

2

+Cl, Hg+S (do both) Cu

2

+Cl = Cu 2 Cl 1 Zn

2

+Cl = Zn 2 Cl 1 = CuCl

2

= ZnCl

2

= copper(II) chloride = zinc chloride Co

2

+Cl = Co 2 Cl 1 = CoCl

2

= cobalt(II) chloride Hg+S = Hg

1

S

2

= Hg

2

S = mercury(I) sulfide Hg+S = Hg

2

S

2

= HgS = mercury(II) sulfide

Compounds containing polyatomic ions

• So far we have given valences to single atoms • Li + O Li

1

O

2

 Li

2

O • Groups of atoms can also have valences “ Polyatomic ions ” are groups of atoms that interact as a single unit. • E.g. OH 1 , (SO 4 ) 2 . Ba 3 (PO 4 ) 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 • Name: Ca(OH)

2 ,

CuSO -ate

4 ,

or NH

4

-ite • Note that most are negative, except ammonium NO

3

not -ide

,

Co

2

(CO

3

)

3

Compounds containing polyatomic ions

Ca(OH)

2

CuSO

4

NH

4

NO

3

Co

2

(CO

3

)

3

- calcium hydroxide - copper(II) sulfate - ammonium nitrate - cobalt(III) carbonate

1 mono 2 3 di tri

Naming covalent compounds

4 tetra 5 penta 6 hexa • -ide ending, each element has “ prefix ” • prefix refers to # of atoms - not valence N 2 O 4 = dinitrogen tetroxide • Exception: drop mono for first element CO 2 = carbon dioxide • The first vowel is often dropped to avoid the combination of “ ao ” or “ oo ” .

7 hepta 8 octa 9 nona 10 deca CO = carbon monoxide (monooxide) P 4 O 10 = tetraphosphorus decoxide SO 2 = sulfur dioxide (dioxide) • Name: CCl 4 , P 2 O 3 , IF 7

Write and name the following covalent compounds (IUPAC)

CCl 4

carbon tetrachloride

P 2 O 3

diphosporus trioxide

IF 7

iodine heptafluoride

Working backwards: name to formula

• It ’ s possible to determine a formula from a name • E.g. What is the formula of sodium oxide?

• To get the answer, first write the valences: Na Cu 1 2 O O 2 2   Na Cu 2 O • What is the formula of copper(II) oxide?

2 O 2  CuO • For covalent compounds, simply use the prefixes to tell you the number of each element: • What is the formula for dinitrogen trioxide?

N 2 O 3 • Give formulae for: lithium sulfide, dinitrogen monoxide, lead(IV) sulfate

Write and name the following covalent compounds (IUPAC) lithium sulfide Li

1

S

2 

Li

2

S dinitrogen monoxide N

2

O lead(IV) sulfate Pb

4

(SO

4

)

2 

Pb

2

(SO

4

)

4 

Pb(SO

4

)

2

Assignment

1. Name each according to IUPAC rules: a) ZnS, b) FeCl 3 , c) CaCO 3 , d) P 2 O 5 , e) NaCN, f) N 2 F 2 , g) MgHPO 4 , h) Cu(BrO 3 ) 2 , i) K 2 O, j) BF 3 1. Give the valence of a) Fe in FeO, b) Mn in MnO 2 3. Write formulas for: a) sodium oxide, b) potassium iodide, c) plumbic sulfide, d) mercury(I) oxide, e) ferrous oxide, f) iron(II) phosphate, g) copper(II) fluoride, h) dichlorine monoxide, i) silver sulfide, j) magnesium nitride, k) aluminum hypochlorite, l) iodine pentafluoride, m) calcium chromate, n) diphosphorus pentasulfide

Answers – 1, 2

a) zinc sulfide b) iron(III) chloride c) calcium carbonate d) diphosporus pentoxide e) sodium cyanide f) dinitrogen difluoride g) magnesium hydrogen phosphate h) copper(II) bromate i) potassium oxide j) boron trifluoride 2 a) 2 b) 4

a) Na

2

O b) KI c) PbS

2

d) Hg

2

O e) FeO Answers – 3 h) Cl

2

O i) j) Ag

2

S Mg

3

N

2

k) Al(ClO)

3

l) IF

5

f) Fe

3

(PO

4

)

2

g) CuF

2

m) CaCrO

4

n) P

2

S

5

Naming Bases

• Bases contain an OH group • C

6

H

12

O

6

does not have an OH group • If an OH group is present it will be clearly indicated: e.g. NaOH, Ca(OH)

2

• Also notice that bases have a metal (or positive ion such as NH

4 +

at their beginning) • Bases are named like other ionic compounds: • +ve is named first, followed by the polyatomic ion Ca(OH)

2

CuOH - calcium hydroxide - copper(I) hydroxide aluminum hydroxide ammonium hydroxide - Al(OH) - NH

4

OH

3

Naming Acids: Binary acids

• All acids start with H (e.g. HCl, H

2

SO

4

) • 2 acids types exist: binary acids and oxyacids Binary: H + non-metal. E.g. HCl Oxy: H + polyatomic ion. E.g. H

2

SO

4

• Each have different naming rules.

Binary acids: naming depends on state of acid • If it ’ s not aqueous: hydrogen + non-metal HCl(g) = hydrogen chloride • If it is aqueous: hydro + non-metal + ic acid HCl(aq) = hydrochloric acid (aqueous hydrogen chloride) H

2

S(aq)

hydrosulfuric acid

HI(aq) H

2

S(g)

hydroiodic acid hydrogen sulfide

Naming Acids: Oxyacids

• Naming does not depend on the state (aq) • 1) name the polyatomic ion 2) replace ate with ic, ite with ous 3) change non-metal root for pronunciation 4) add “ acid ” to the name E.g. H

2

SO

3

1) sulphite, 3) sulphurous , 2) sulphous, 4) sulphurous acid HNO

2

hypochlorous acid H

3

PO

4

(aq) carbonic acid

Naming Acids: Oxyacids

HNO

2

- nitrous acid H

3

PO

4

(aq) - phosphoric acid hypochlorous acid - HClO carbonic acid - H

2

CO

3

Assignment: give formula or name

a) chloric acid b) hydrosulfuric acid c) hydrobromic acid d) phosphorous acid e) iodic acid f) HCl(g) g) HCl(aq) h) H

2

SO

4

(s) i) H

2

SO

4

(aq) j) HClO

2

k) HF(aq) a) HClO

3

b) H 2 S(aq) c) HBr(aq) d) H

3

PO

3

e) HIO 3 f) hydrogen chloride g) hydrochloric acid h) sulfuric acid i) sulfuric acid j) chlorous acid k) hydrofluoric acid

Hydrates

• Some compounds contain H

2

O in their structure. These compounds are called hydrates.

• This is different from (aq) because the H

2

O is part of the molecule (not just surrounding it).

• The H

2

O can usually be removed if heated.

• A dot separates water: e.g. CuSO

4

•5H

2

O is copper(II) sulfate pentahydrate.

• A greek prefix indicates the # of H

2

O groups.

Na

2

SO

4

•10H

2

O NiSO

4

•6H

2

O sodium sulfate decahydrate nickel(II) sulfate hexahydrate sodium carbonate monohydrate barium chloride dihydrate Na

2

CO

3

•H

2

O BaCl

2

•2H

2

O