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Lesson4

ReaconsofGroup2metals

Describethereaconsofgrouptwometals Writehalfequaonsforthereaconofgroup2

metalswithoxygenandwater Describethereaconsofgrouptwometaloxides Describethereaconsofgrouptwometal

hydroxides

Objecves

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Reac%vityofgroup2elements

Group2elementsarestrongREDUCINGagentsWhentheyreacttheyareOXIDISEDOILRIG

MM2+

+2e-

Predictthetrendinreacvitygoingdownthegroup

Reac%onwithoxygen

2Ca(s)+O2(g)2CaO(s)Whataretheoxidaonnumbersforeachelementbeforeandaerthereacons?

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Reac%onwithwater

Ca(s)+2H2O(l)Ca(OH)2(s)+H2(g)Whataretheoxidaonnumbersforeachelementbeforeandaerthereacons?

Group2oxidesandhydroxidesarebasesand

neutraliseacids.Whendissolvedinwaterthey

haveahighpH(10-11)

MgO(s)+2HCl(aq)MgCl2(aq)+H2O(l)

Ca(OH)2(s)+2HCl(aq)CaCl2+2H2O(l)

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AfLWhenyoudissolveMgOinwaterithasahighpH.Explainwhythisis?

Answer

TohaveahighpHtheremustbehydroxideionspresent.

WhenMgOisdissolvedinwateritreactswiththewatertoproduceMg(OH)2

MgO(s)+H2O(l)Mg(OH)2(aq)

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Markscheme

Group2carbonates

Thermaldecomposionbyheatmoredifficultgoingdownthegroup

MgCO3(s)MgO(s)+CO2(g)InotherwordsTHERMALSTABILITYincreasesasyougodownthegroup.

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Markscheme

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Markscheme

Howtowritehalf-equaonsAhalfequaonshowsthereagentbeingoxidisedORthereagentbeingreducedseparately.Itshowswhatishappeningtotheelectrons

CaCa2++2e-

O2+4e-2O2-

AemptthehalfequaonforthethereaconofCawithH2O

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PlenaryreaconwebUsingpages88-91ofthetextbooktoguideyoudrawareaconwebforthereaconsofmagnesium.

Completequeson4onpage98forhomework.

Periodicity

Lesson5praccalexperimentstoinvesgategroup2reacons

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Objecves Planandexecuteapraccalexperimenttoinvesgatethereaconsofgroup2metalsoxidesandhydroxides

Iden(fythereaconstakingplaceusingtheworksheetprovided

Write-upyourpraccalincludingmethod,resultsandconclusionthisshouldincludeadescriponofhowyourresultssupportorcontrastwithchemicaltheory

Periodicity

Lesson6-Halideions

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Must(Cgrade)RecognisethathalogensreactbygainingelectronstobecomehalideionsUsetheprecipitaonofsilverhalideasatestforhalideionsKnowsomeoftheusesofhalidesShould(Bgrade)RecapthereacvityseriesofhalidesthathalogensbecomelessreacvedownthegroupInterpretthetestsforhalidetodeterminewhetheragivensoluonisachloride,bromideoriodideWritehalfequaonsforthereduconofhalogenstoformhalideionsCould(Agrade)Describethedisplacementofhalogensfromhalidesaltsaccordingtothereacvityseriesofthehalogens

Writeequaonstoshowthedisproporonaonofchlorineinwaterandsodiumhydroxide

Halidesalts

NaI NaBr NaCl

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Silverhalidesaresolidsandformaprecipitatewhensilvernitrateisadded

NaCl+AgNO3AgCl+NaNO3

NaBr+AgNO3AgBr+NaNO3

NaI+AgNO3AgI+NaNO3

Creamprecipitate

Whiteprecipitate

Yellow/creamprecipitate

Whiteprecipitate

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Hastheionicequaon

WecallthehighlysolubleNa+andNO3-ionsSPECTATOR

ionsDontforgetthestatesymbols(aq)(s)(l)(g)

Howtowriteionicequaons

ConfirmingthetestswhencolourisnotconclusiveAgCldissolvesindilute/concammonia

AgBrdissolvesinconcammoniaAgIdoesnotdissolve

**Usethetableprovidedandfillinyourobservaons

Isitcream,oristhatyellow?

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Fluorineisthemostreacvehalogen.

Ingroup7reacvity(oxidisingpower)decreasesasyougodownthegroup.

Thisisbecausegainingelectronstoformnegaveions.Astheatomicradius,shieldingandsothearacveforceofthenucleusincreasesgoingdownthegroup,reacvitydecreases.

Trendinreacvity

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Markscheme

Halogensreactbygaininganelectron

Halogensaremorereacvethehighertheyareinthe

groupMorereacvehalogenscandisplacelessreacvehalogensfromsoluon

Reacvityanddisplacement

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Displacementreacons

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Markscheme

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Markscheme

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Markscheme

Whenhalogensdissolveinwatertheyareoxidisedandreducedatthesamemethisiscalled

disproporonaonEgCl2(aq)+H2O(l)HCl(aq)+HOCl(l)

Disproporonaoninwater

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CanyougivetheoxidaonnumbersoftheClatoms?Canyouwriteanionicequaon?

Cl2(aq)+2NaOH(aq)NaCl(aq)+NaClO(aq)+H2O(l)

Cl2(aq)+2OH-(aq)Cl-(aq)+ClO-(aq)+H2O(l)

DisproporonaoninNaOHdiluteThereaconofCl2withdiluteaqueousNaOHmakesbleach(NaClO)

CanyougivetheoxidaonnumbersoftheClatoms?Canyouwriteanionicequaon?3Cl2+6NaOHNaClO3+5NaCl+3H2O

3Cl2(aq)+6OH-(aq)5Cl-(aq)+ClO3-(aq)+3H2O(l)

DisproporonaoninNaOH

ThereaconofCl2withconcentratedNaOHmakestheweedkillerNaClO3

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ChlorineanddrinkingwaterAddionofchlorinetodrinkingwaterisbeneficialbecauseitkillsbacteriamakingwatersafetodrink.

Chlorineistoxicandusingitishazardous

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Markscheme

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Markscheme

Plenarytextbookquesons

Aemptqueson7onpage97(pastexampaperqueson).

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Periodicity

Lesson7thereaconsofhalogens

praccal

Objecves

Planandexecuteapraccalexperimenttoinvesgatethereaconsofhalogens

Iden(fytheREDOXreaconstakingplaceusingtheworksheetprovided

Write-upyourpraccalincludingmethod,resultsandconclusionthisshouldincludeadescriponofhowyourresultssupportorcontrastwithchemicaltheory

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Morepraccewringionicequaons

PraccalworkonREDOXontheworksheet.REDOXmeanssomethingisoxidisedandsomethingisreduced.1)Conducttheexperiments2)Asyouaredoingtheexperimentsreadthroughthe

equaonsandtryandworkoutwhatisbeingoxidisedandwhatisbeingreduced.3)Haveagoatidenfyingoxidaonnumbers.