compound names and formulas tutorial and worksheet

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NamingCompoundsTutorialandWorksheet
Sinceweusedifferentmethodsinnamingbinarycovalent(molecular)
compoundsandioniccompounds,thefirststepinnamingorwritingtheformula
ofacompoundistodeterminewhichofthe2compoundclassesitbelongs.This
canbedoneasfollows:
DetermineiftheCompoundisBinaryCovalent (Molecular)orIonic:
Doesthecompoundcontainonly twotypesofnonmetalelements?
Yes
No
BinaryCovalent
IonicCompound
(Molecular)Compound
Binary covalent compounds will contain only two types of non-metal elements.
Theremaybemorethanoneofeachelement.ForexampleCO2containsjusttwo
types of elements, carbon and oxygen. We will discuss naming covalent
compoundsthatcontainmorethantwotypesofelements,likeglucoseC6H12O6,
inlaterchapters.
Onceitisdeterminedthatthecompoundisionicorcovalent,thestudentcanbe
askedtodoeitherofthefollowing:
1)Giventhenameofthecompound,writetheformula.
Or
2)Giventheformulaofthecompound,writethename.
Inthistutorialwewillreviewtheprocessforachievingthese2objectivesand
practicewithsomeworksheetproblems.First,wewillreviewandpracticehowto
writeformulasforcompoundswhengiventhecompound’sname.Second,we
willreviewandpracticehowtowritethenameofacompoundwhengiventhe
compound’sformula.
1
GiventheNameoftheCompound,WritingFormulasforCompounds
DetermineiftheCompoundisBinaryCovalent(Molecular)orIonic:
Doesthecompoundcontainonlytwotypesofnonmetalelements?
Yes
BinaryCovalent(Molecular)
Compound:
1) Writethesymbolofthefirstelementin
thecompound’sname,thenthesymbolof
thesecondelementinthecompound’s
name.
2) Indicatehowmanyatomsofeachelement
themoleculecontainsusingsubscripts
aftertheatomicsymbol.
• Thenumbersofatomsaregiveninthe
molecule’snameinGreekprefixes
• NOTE:IfthereisnoGreekprefixin
frontofthefirstelementinthe
namethatimpliesthenumberis1.
No
IonicCompound:
1) Writethesymbol/formulaofthefirstion
inthecompound’sname,thenthe
symbol/formulaofthesecondioninthe
compound’sname.
2) Indicatetheratiooftheionsinthe
compoundusingsubscriptsaftereach
ion.
• Theratiooftheionsisdeducedby
balancingthechargesoftheions.
• IMPORTANT:Whenthereismore
thanoneofapolyatomicioninthe
formulaunitweuseparenthesis.
ExampleMg(NO3)2
2
WritingtheFormulasofIonicCompounds
Example:Writetheformulaforcalciumbromide.
1) Writethesymbol/formulaofthefirstioninthecompound’sname,thenthe
symbol/formulaofthesecondioninthecompound’sname.
CaBr
2) Indicatetheratiooftheionsinthecompoundusingsubscriptsaftereachion.
• Thisstepinvolvesfillinginthesubscriptsboxesaswedidinthelecture:
CaBr
•
•
Theratiooftheionsisdeducedbybalancingthechargesoftheions.
• Thisisdonesothatthetotalchargeinthecrystal,whenlargenumbersof
cationsandanionscombine,isequaltozero.
• Wefindtheion’schargefromitspositionontheperiodictableorwelook
itupinatableinthecaseofpolyatomicions.
• Transitionmetalwithvaryingchargeswillbewritteninthecompound
nameinRomannumerals.
First,temporarilywritethechargeofeachionabovetheion’ssymbol.
2+1-
CaBr
Next,placenumbersinthesubscriptssuchthatthetotalchargeofthecompound
iszero.Notethatinthisexample,weneedtwobromideions,eachhasacharge
of(1-)tocancelthe(2+)chargeofthecalciumion:
• 2(-1)+(+2)=0zerototalcharge.
2+1-
•
Ca1Br2=CaBr2
WesawashortcutwaytodothiscalledtheCriss-CrossMethod(seeyour
chapter3notes)
2+1-
•
Ca1Br2=CaBr2
•
Note,wedonotleavethechargeswrittenabovethesymbolsinthe
completedformula.
IMPORTANT:Whenthereismorethanoneofapolyatomicionintheformula,weuse
parenthesis.
•
Notapplicableinthisexamplesincetherearenopolyatomicionsincalcium
bromide.
3
Examples:WritingtheFormulasofIonicCompounds
Writetheformulaformagnesiumnitrate.
1) Writethesymbol/formulaofthefirstioninthecompound’sname,thenthe
symbol/formulaofthesecondioninthecompound’sname.
• Whenyouseeapolyatomicion(nitrate),lookuptheformulaandcharge
inthetableofpolyatomicions.
MgNO3
2) Indicatetheratiooftheionsinthecompoundusingsubscriptsaftereachion.
a. Thisstepinvolvesfillinginthesubscriptsboxesaswedidinthelecture:
MgNO3
•
•
Theratiooftheionsisdeducedbybalancingthechargesoftheions.
• Thisisdonesothatthetotalchargeinthecrystal,whenlargenumbersof
cationsandanionscombine,isequaltozero.
• Wefindtheion’schargefromitspositionontheperiodictableorwelook
itupinatableinthecaseofpolyatomicions.
• Transitionmetalwithvaryingchargeswillbewritteninthecompound
nameinRomannumerals.
First,temporarilywritethechargeofeachionabovetheion’ssymbol.
2+1-
MgNO3
Next,placenumbersinthesubscriptssuchthatthetotalchargeofthecompound
iszero.Notethatinthisexample,weneedtwonitrateions,eachhasachargeof
(1-)tocancelthe(2+)chargeofthemagnesiumion:
• 2(-1)+(+2)=0zerototalcharge.
2+1-
•
Mg1NO32
• WesawashortcutwaytodothiscalledtheCriss-CrossMethod(seeyour
chapter3notes)
2+1-
Mg1NO32
IMPORTANT:Whenthereismorethanoneofapolyatomicionintheformulaunitweuseparenthesis.
Thereare2ionsofnitrateinmagnesiumnitrate
Mg1NO32=Mg(NO3)2
Incompoundwherethereisjustoneformulaunitofapolyatomicion,noparenthesisare
needed.Anexampleofthisissodiumnitrate:NaNO3
4
Examples:WritingtheFormulasofIonicCompounds
Writetheformulaforiron(II)phosphate.
1) Writethesymbol/formulaofthefirstioninthecompound’sname,thenthe
symbol/formulaofthesecondioninthecompound’sname.
• Whenyouseeapolyatomicion(phosphateinthiscase),lookupthe
formulaandchargeinthetableofpolyatomicions.
FePO4
2) Indicatetheratiooftheionsinthecompoundusingsubscriptsaftereachion.
b. Thisstepinvolvesfillinginthesubscriptsboxesaswedidinthelecture:
FePO4
•
•
Theratiooftheionsisdeducedbybalancingthechargesoftheions.
• Thisisdonesothatthetotalchargeinthecrystal,whenlargenumbersof
cationsandanionscombine,isequaltozero.
• Wefindtheion’schargefromitspositionontheperiodictableorwelook
itupinatableinthecaseofpolyatomicions.
• Transitionmetalwithvaryingchargeswillbewritteninthecompound
nameinRomannumerals.
• Inthisexample,nowweknowthechargeontheFeionis2+
First,temporarilywritethechargeofeachionabovetheion’ssymbol.
2+3-
FePO4
Next,placenumbersinthesubscriptssuchthatthetotalchargeofthecompound
iszero.Notethatinthisexample,weneedtwophosphateions,eachhasa
chargeof(3-)andthreeFe2+ionstobalancethecharge:
• 2(-3)+3(-2)=0zerototalcharge.
2+3-
•
Fe3PO42
WesawashortcutwaytodothiscalledtheCriss-CrossMethod(seeyour
chapter3notes)
2+3-
•
Fe3PO42
IMPORTANT:Whenthereismorethanoneofapolyatomicionintheformulaunitweuseparenthesis.
Thereare2ionsofphosphateiniron(II)phosphate.
Fe3PO42=Fe3(PO4)2
5
Examples:WritingtheFormulasofIonicCompounds
Writetheformulaforbariumsulfide.
1) Writethesymbol/formulaofthefirstioninthecompound’sname,thenthe
symbol/formulaofthesecondioninthecompound’sname.
BaS
2) Indicatetheratiooftheionsinthecompoundusingsubscriptsaftereachion.
• Thisstepinvolvesfillinginthesubscriptsboxesaswedidinthelecture:
BaS
•
•
Theratiooftheionsisdeducedbybalancingthechargesoftheions.
• Thisisdonesothatthetotalchargeinthecrystal,whenlargenumbersof
cationsandanionscombine,isequaltozero.
• Wefindtheion’schargefromitspositionontheperiodictableorwelook
itupinatableinthecaseofpolyatomicions.
• Transitionmetalwithvaryingchargeswillbewritteninthecompound
nameinRomannumerals.
First,temporarilywritethechargeofeachionabovetheion’ssymbol.
2+2-
BaS
• Next,placenumbersinthesubscriptssuchthatthetotalchargeofthecompound
iszero.Notethatinthisexample,weneedonesulfideion,withachargeof(2-)
tocancelthe(2+)chargeofthebariumion:
• (-2)+(+2)=0zerototalcharge.
2+2-
Ba1S1=BaS
• WesawashortcutwaytodothiscalledtheCriss-CrossMethod(seeyour
chapter3notes)
2+2-
Ba2S2=BaS
•
Note,thesubscriptsinioniccompoundrepresenttheratioinwhichlarge
numbersofanionsandcationscombinetoformtheioniccompounds.
Sincewewantthelowestratio:weuse1:1,since2:2=1:1
Ba2S2=BaS
6
Writetheformulaforthefollowingioniccompounds:(seenextpageforkey)
sodiumbicarbonate_________________
sodiumfluoride_________________
iron(III)chloride_________________
sodiumcarbonate_________________
copper(II)sulfate_________________
magnesiumhydroxide_________________
bariumnitrate_________________
lithiumsulfate_________________
magnesiumchloride_________________
silvernitrate_________________
aluminumsulfate_________________
calciumhydroxide_________________
calciumsulfate_________________
mercury(II)nitrate_________________
lead(IV)nitrate_________________
magnesiumiodide_________________
sodiumnitride_________________
7
PracticeProblemsKEY
sodiumbicarbonateNaHCO3
sodiumfluorideNaF
iron(III)chlorideFeCl3
sodiumcarbonateNa2CO3
copper(II)sulfateCuSO4
magnesiumhydroxideMg(OH)2
bariumnitrateBa(NO3)2
lithiumsulfateLi2SO4
magnesiumchlorideMgCl2
silvernitrateAgNO3
aluminumsulfateAl2(SO4)3
calciumhydroxideCa(OH)2
calciumsulfateCaSO4
mercury(II)nitrateHg(NO3)2
lead(IV)nitratePb(NO3)4
magnesiumiodideMgI2
sodiumnitrideNa3N
8
WritingtheFormulasofCovalentCompounds
1) Writethesymbol/formulaofthefirstelementinthecompound’sname,thenthe
symbol/formulaofthesecondelementinthecompound’sname.
2)Indicatehowmanyatomsofeachelementthemoleculecontainsusingsubscriptsafterthe
atomicsymbol.
• Thenumbersofatomsaregiveninthemolecule’snameinGreekprefixes
• NOTE:IfthereisnoGreekprefixinfrontofthefirstelementinthename,that
meansthenumberis1.
Example:Writetheformulaofdinitrogentetrafluoride.
1) Writethesymbol/formulaofthefirstelementinthecompound’sname,thenthe
symbol/formulaofthesecondelementinthecompound’sname.
NF
2)Indicatehowmanyatomsofeachelementthemoleculecontainsusingsubscriptsafterthe
atomicsymbol.
NF
•
Thenumbersofatomsaregiveninthemolecule’snameinGreekprefixes.
• dinitrogentetrafluoride
• seeyourchapter3notesforalistoftheGreekprefixes
N2F4
•
NOTE:IfthereisnoGreekprefixinfrontofthefirstelementinthename,then
thenumberis1.
• Examplecarbontetrachloride=CCl4
Example:Writetheformulaofcarbondisulfide.
1) Writethesymbol/formulaofthefirstelementinthecompound’sname,thenthe
symbol/formulaofthesecondelementinthecompound’sname.
CS
2)Indicatehowmanyatomsofeachelementthemoleculecontainsusingsubscriptsafterthe
atomicsymbol.
CS
•
Thenumbersofatomsaregiveninthemolecule’snameinGreekprefixes.
• carbondisulfide
• seeyourchapter3notesforalistoftheGreekprefixes
C1S2=CS2
•
NOTE:IfthereisnoGreekprefixinfrontofthefirstelementinthename,then
thenumberis1.
9
Writetheformulasforthefollowingcovalentcompounds:
SeenextpageforKEY
a. disulfurtetrafluoride_________________________
b. carbontrioxide_________________________
c. nitrogenpentoxide_________________________
d. nitrogentribromide_________________________
e. dinitrogenheptachloride_________________________
f. carbontetrachloride_________________________
g. hydrogenmonochloride_________________________
h. trihydrogenmonophosphide_________________________
i. dihydrogenmonoxide_________________________
10
KEY
a. disulfurtetrafluorideS2F4
b. carbontrioxideCO3
c. nitrogenpentoxideNO5
d. nitrogentribromideNBr3
e. dinitrogenheptachlorideN2Cl7
f. carbontetrachlorideCCl4
g. hydrogenmonochlorideHCl
h. trihydrogenmonophosphideH3P
i. dihydrogenmonoxideH2O
11
GiventheFormulasforCompounds,WritetheName
DetermineiftheCompoundisBinaryCovalent(Molecular)orIonic:
Doesthecompoundcontainonlytwotypesofnonmetalelements?
No
Yes
BinaryCovalent(Molecular)
Compound:
1)Listthenameofthefirstelementinthe
formula.
2)Listthesecondelementandaddthe"ide"
suffix. 3)UseGreekprefixestoindicatethe
numberofeachatomintheformula.
• Exception:Donotusemono-forthe
firstelementinthename.
• TheooraattheendoftheGreek
prefixisdroppedwhentheelement
namebeginswithavowel.
IonicCompound:
1)Writethecationnamefirst,then
nametheanion.
• Monoatomicanionsusethe“ide”
suffix
2)Ifthecationisoneofthemetalswith
variouscharges,writethecharge
usingparenthesisandRoman
numeralsafterthemetalname.
12
WritingtheNamesofIonicCompounds
Example:WritethenameforCaBr2
1)
Writethecationnamefirst,thennametheanion.
• monoatomicanionsusethe“ide”suffix
calciumbromide
2)Ifthecationisoneofthetransitionmetalswithvariouscharges,writethechargeusing
parenthesisandRomannumeralsafterthemetalname.
• Notnecessaryhere,thereisnotatransitionmetalpresent
Example:WritethenameforMg(NO3)2
1) Writethecationnamefirst,thennametheanion.
• monoatomicanionsusethe“ide”suffix
• Herewenoticethattheanionisapolyatomicion.Getthenamefromthe
polyatomiciontable(inyournotesortextbook).Youwillbegivenacopyof
thepolyatomiciontableonyourexams.
• Donotchangethesuffixto“ide”withpolyatomicions:
magnesiumnitrate
2)Ifthecationisoneofthetransitionmetalswithvariouscharges,writethechargeusing
parenthesisandRomannumeralsafterthemetalname.
• Notnecessaryhere,thereisnotatransitionmetalpresent
13
WritingtheNamesofIonicCompounds
Example:WritethenameforCuF2
1)
Writethecationnamefirst,thennametheanion.
• monoatomicanionsusethe“ide”suffix
copperfluoride
2)Ifthecationisoneofthetransitionmetalswithvariouscharges,writethechargeusing
parenthesisandRomannumeralsafterthemetalname.
copper(?)fluoride
•
Wemustfigureoutwhatthechargeisonthecopper,wecandeducethecharge
onthetransitionmetalcationsfromthechargeontheanions
• Recallthatthetotalchargeforanycompoundmustequalzero.
• Sincetherearetwofluorides,eachwithachargeof(1-)andthereisonly
onecopper,wecanconcludethatthechargeonthecoppermustbe(2+).
• Youcanthinkofthisasthereversecriss-cross!Seechapter3
notesformoredetails.
copper(II)fluoride
writethechargeinparenthesisin
Romannumeralsafterthecationname
14
Writethenamesofthefollowingcompounds:
Seenextpageforkey
NaCl__________________________________________
Fe2(CO3)3__________________________________________
Cu(OH)2__________________________________________
(NH4)2SO4__________________________________________
LiNO3__________________________________________
BaSO4__________________________________________
Mg(NO3)2__________________________________________
AgCl__________________________________________
Al(OH)3__________________________________________
CaSO4__________________________________________
FeS__________________________________________
FeCl3__________________________________________
NaI__________________________________________
MgCO3__________________________________________
15
KEY
NaClsodiumchloride
Fe2(CO3)3iron(III)carbonate
Cu(OH)2copper(II)hydroxide
(NH4)2SO4ammoniumsulfate
LiNO3lithiumnitrate
BaSO4bariumsulfate
Mg(NO3)2magnesiumnitrate
AgClsilverchloride
•
(note:silverisoneofthetransitionmetalsthatonlyoccursasa(1+)ion)
Al(OH)3aluminumhydroxide
CaSO4calciumsulfate
FeSIron(II)sulfide
FeCl3iron(III)chloride
NaIsodiumiodide
MgCO3magnesiumcarbonate
16
WritingtheNamesofCovalentCompounds
1)Listthenameofthefirstelementintheformula.
2)Listthesecondelementandaddthe–idesuffix. 3)UseGreekprefixestoindicatethenumberofeachatomintheformula.
• Exception:donotusemono-forthefirstelementinthename.
• TheooraattheendoftheGreekpre-fixisusuallydroppedwhentheelement
namebeginswithavowel
Example:WritethenameforN2S4
1)Listthenameofthefirstelementintheformula.
nitrogen
2)Listthesecondelementandaddthe–idesuffix. nitrogensulfide
3)UseGreekprefixestoindicatethenumberofeachatomintheformula.
• SeeyourtextbookorlecturenotesforatableoftheGreekprefixes.
____nitrogen_____sulfide
dinitrogentetrasulfide
•
•
Exception:donotusemono-forthefirstelementinthename.
• Notapplicableinthisexample
TheooraattheendoftheGreekpre-fixisusuallydroppedwhentheelement
namebeginswithavowel
• Notapplicableinthisexample
Example:WritethenameforSO3
1)Listthenameofthefirstelementintheformula.
sulfur
2)Listthesecondelementandaddthe–idesuffix. sulfuroxide
3)UseGreekprefixestoindicatethenumberofeachatomintheformula.
____sulfur_____oxide
sulfurtrioxide
•
•
Exception:donotusemono-forthefirstelementinthename.
• NOTE,wedidnotwritemonosulfurbecauseofthisrule!
TheooraattheendoftheGreekpre-fixisusuallydroppedwhentheelement
namebeginswithavowel
• Notapplicableinthisexample
17
Example:WritethenameforSO2
1)Listthenameofthefirstelementintheformula.
sulfur
2)Listthesecondelementandaddthe–idesuffix. sulfuroxide
3)UseGreekprefixestoindicatethenumberofeachatomintheformula.
____sulfur_____oxide
sulfurdioxide
•
•
Exception:donotusemono-forthefirstelementinthename.
• NOTE,wedidnotwritemonosulfurbecauseofthisrule!
TheooraattheendoftheGreekpre-fixisusuallydroppedwhentheelement
namebeginswithavowel
• Notapplicableinthisexample
Example:WritethenameforCO
1)Listthenameofthefirstelementintheformula.
carbon
2)Listthesecondelementandaddthe–idesuffix. carbonoxide
3)UseGreekprefixestoindicatethenumberofeachatomintheformula.
____carbon_____oxide
carbonmonoxide
•
•
Exception:donotusemono-forthefirstelementinthename.
• NOTE,wedidnotwritemonocarbonbecauseofthisrule!
TheooraattheendoftheGreekpre-fixisusuallydroppedwhentheelement
namebeginswithavowel
• NOTE,wedidnotwritemonooxidebecauseofthisrule!
Writethenamesofthefollowingcompounds:
Seenextpageforkey
a. Br2I4________________________________________
b. P5F8________________________________________
c. NO5________________________________________
• Remember:TheooraattheendoftheGreekpre-fixisusuallydroppedwhen
theelementnamebeginswithavowel
d. NBr3________________________________________
e. N2O5________________________________________
f. BrCl3________________________________________
g. H2S________________________________________
h. N2O________________________________________
18
a. Br2I4dibrominetetriodide
KEY
b. P5F8pentaphosphorusoctafluoride
c. NO5nitrogenpentoxide
o TheooraattheendoftheGreekpre-fixisusuallydroppedwhentheelement
namebeginswithavowel
§ NOTE,wedidnotwritepentaoxygenbecauseofthisrule!
d. NBr3nitrogentribromide
e. N2O5dinitrogenpentoxide
f. BrCl3brominetrichloride
g. H2Sdihydrogenmonosulfide
h. N2Odinitrogenmonoxide
19
20
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