Naming Chemicals

AP ChemistryAP Chemistry

Classes of Chemicals

ElementsElements Ionic CompoundsIonic Compounds Covalent CompoundsCovalent Compounds Organic CompoundsOrganic Compounds

Elements

All elements on the periodic tableAll elements on the periodic table All just one word: iron, sodium, neon, etc.All just one word: iron, sodium, neon, etc. All neutrally chargedAll neutrally charged Mostly monatomic: Fe, Na, NeMostly monatomic: Fe, Na, Ne Some Some didiatomic:atomic: H H2 2 OO2 2 NN2 2 ClCl2 2 BrBr2 2 II2 2 FF22

Some Some polypolyatomic: Satomic: S88, P, P44

Gold

Ionic Compounds

Made of one metal positive ion (cation) and Made of one metal positive ion (cation) and one non-metal negative ion (anion)one non-metal negative ion (anion)

Always two words starting with the cation Always two words starting with the cation and ending with the anionand ending with the anion

Cation is same name as elementCation is same name as element Anion always has a different suffixAnion always has a different suffix

Sodium chloride

Anion Suffixes

MonatomicMonatomic atoms end with atoms end with –ide–ide Oxygen atom = OOxygen atom = O OxOxideide ion = O ion = O-2-2

Sulfur atom = SSulfur atom = S SulfSulfideide ion = S ion = S-2-2

Chlorine atom = ClChlorine atom = Cl ChlorChlorideide ion = Cl ion = Cl-1-1

Oxy-Anions

Oxy-Oxy-anions end in anions end in –ate–ate Sulfate = SOSulfate = SO44

-2-2 Chlorate = ClOChlorate = ClO33-1-1

Chromate = CrOChromate = CrO44-2-2 Nitrate = NONitrate = NO33

-1-1

If the anion is further oxidized then add the If the anion is further oxidized then add the prefix prefix per-per-

ClOClO33-1-1 = chlorate = chlorate ClO ClO44

-1-1 = = perperchloratechlorate

Less Oxidation

If the anion is less oxidized by 1 then change If the anion is less oxidized by 1 then change the –the –ateate suffix to an – suffix to an –iteite suffix suffix

SOSO44-2-2 = sulf = sulfateate SOSO33

-2-2 = sulf = sulfiteite ClOClO33

-1-1 = chlor = chlorateate ClOClO22-1-1 = chlor = chloriteite

If the anion is less oxidized If the anion is less oxidized againagain then add then add the prefix the prefix hypo-hypo-

ClOClO-1-1 = = hypohypochlorchloriteite SOSO22-2-2 = = hypohyposulfsulfiteite

Summary

Per- -atePer- -ate -ate-ate -ite-ite Hypo- -iteHypo- -iteChlor-Chlor- ClOClO44

-1-1

PerchloratePerchlorateClOClO33

-1-1

chloratechlorateClOClO22

-1-1

chloritechloriteClOClO-1-1

hypochloritehypochlorite

Sulf-Sulf- SOSO44-2-2

sulfatesulfateSOSO33

-2-2

SulfiteSulfiteSOSO22

-2-2

HyposulfiteHyposulfite

Nitr-Nitr- NONO33-1-1

NitrateNitrateNONO22

-1-1

NitriteNitrite

Phos-Phos- POPO44-3-3

PhosphatePhosphatePOPO33

-3-3

PhosphitePhosphite

Sulfur Replacement

If one of the oxygens in an oxy-anion is If one of the oxygens in an oxy-anion is replaced with a sulfur then add the prefix replaced with a sulfur then add the prefix thio-thio-

SOSO44-2-2 = sulfate = sulfate SS22OO33

-2-2 = = thiosulfatethiosulfate

SOSO33-2-2 = sulfite = sulfite SS22OO22

-2-2 = thiosulfite = thiosulfite CNOCNO-1-1 = cyanate = cyanate CNSCNS-1-1 = thiocyanate = thiocyanate

Anion Summary

Mon-atomic anions end in –ideMon-atomic anions end in –ide Oxy-anions end in –ate or –iteOxy-anions end in –ate or –ite Add prefixes per- and hypo- when Add prefixes per- and hypo- when

necessarynecessary Add thio- prefix when a sulfur replaces and Add thio- prefix when a sulfur replaces and

oxygenoxygen

Combining Ions•Ionic compounds are always neutrally charged so the number of each ion within the compound is fixed •Sodium oxide:

Na+1 O-2 Since the compound must be neutral we need another positive charge

Na+1 Now we have two sodium atoms to balance out the oxide so the final formula is:

Na2O

Parenthesis

Use parenthesis for multiple polyatomic Use parenthesis for multiple polyatomic ionsions

Aluminum chromate

Al+3 CrO4-2

Al2(CrO4)3

Be careful of Hydroxides!Calcium hydroxide

Ca+2 OH-1

Ca(OH)2CaOH2

Transition Metals

Transition Metals

Transition Metals often have more than one Transition Metals often have more than one chargecharge

Examples: FeExamples: Fe+2+2 and Fe and Fe+3+3

This makes a difference in formulae:This makes a difference in formulae: Iron chloride could be:Iron chloride could be: FeClFeCl22 or FeCl or FeCl33

So what do we do? Since FeClSince FeCl22 and FeCl and FeCl33 are obviously not the same are obviously not the same

compound, they can’t both have the same name.compound, they can’t both have the same name. We differentiate them by using a Roman Numeral We differentiate them by using a Roman Numeral

to indicate the charge on the transition metalto indicate the charge on the transition metal FeFe+2+2 and Cl and Cl-1-1 FeCl FeCl22 = iron (II) chloride = iron (II) chloride FeFe+3+3 and Cl and Cl-1-1 FeCl FeCl33 = iron (III) chloride = iron (III) chloride Be sure to note that the roman numeral indicates Be sure to note that the roman numeral indicates

chargecharge and not and not numbernumber..

Quick practice Sodium bromideSodium bromide NaBrNaBr

• Calcium oxide • CaO• Aluminum nitrate • Al(NO3)3

• Ammonium phosphate • (NH4)3PO4

• Barium hydroxide • Ba(OH)2

• Copper (I) sulfide • Cu2S• Copper (II) sulfate • CuSO4

• Iron (III) dichromate • Fe2(Cr2O7)3

More practice Potassium hypochloritePotassium hypochlorite KClOKClO

• Sodium sulfite • Na2SO3

• Aluminum bromate • Al(BrO3)3

• Ammonium phosphite • (NH4)3PO3

• Magnesium nitrite • Mg(NO2)2

• Iron (III) perchlorate • Fe(ClO4)3

• Strontium cyanate • Sr(CNO)2

• Copper (I) thiosulfate • Cu2S2O3

Covalent Compounds

Comprised of two or more non-metals Comprised of two or more non-metals covalently bondedcovalently bonded

Start with less electronegative and end with Start with less electronegative and end with more electronegativemore electronegative

Name as normal except that all compounds Name as normal except that all compounds change the second element to an –change the second element to an –ideide endingending

Covalent Examples

CO = carbon oxCO = carbon oxideide CSCS22 = carbon sulf = carbon sulfideide NFNF33 = nitrogen fluor = nitrogen fluorideide

Notice in each example the more Notice in each example the more electronegative atom is second and ends in electronegative atom is second and ends in -ide-ide

Problem

Covalent compounds can combine in Covalent compounds can combine in multiple proportions- that is there can be multiple proportions- that is there can be more than one ratio of atoms in a compoundmore than one ratio of atoms in a compound

COCO vs. vs. COCO22

They can’t both be carbon oxideThey can’t both be carbon oxide NONO22 vs.vs. NN22OO44

They can’t both be nitrogen oxideThey can’t both be nitrogen oxide

Solution?

Use prefixes to indicate the number of Use prefixes to indicate the number of covalently bonded atoms present in the covalently bonded atoms present in the moleculemolecule

COCO vs.vs. COCO22

Carbon Carbon monmonoxideoxide Carbon Carbon didioxideoxide

Prefixes 11 22 33 44 55 66 77 88 99 1010

Mono-Mono- Di-Di- Tri-Tri- Tetra-Tetra-

Hexa-Hexa- Penta-Penta-

Hepta-Hepta- Octa-Octa- Nona-Nona- Deca-Deca-

Overall Covalent Rules Comprised of two or more non-metals covalently Comprised of two or more non-metals covalently

bondedbonded Start with less electronegative and end with more Start with less electronegative and end with more

electronegativeelectronegative Name as normal except that all compounds change Name as normal except that all compounds change

the second element to an –the second element to an –ideide ending ending Add a prefix to indicate number of atoms in the Add a prefix to indicate number of atoms in the

compoundcompound The second atom ALWAYS gets a prefixThe second atom ALWAYS gets a prefix The first atom can ignore MONO-The first atom can ignore MONO-

Practice COCO Carbon monoxideCarbon monoxide NN22OO55

Dinitrogen pentoxideDinitrogen pentoxide PClPCl55

Phosphorus pentachloridePhosphorus pentachloride

SOSO33 Sulfur trioxideSulfur trioxide

NN22OO Dinitrogen monoxideDinitrogen monoxide