Group 14 periodic table

7/27/2019 Group 14 periodic table

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SEK. MEN. KEB. SULTAN ISMAIL, JOHOR BAHRU.INORGANIC CHEMISTRY/ UPPER SIX/ 2013TOPIC : GROUP 14 ELEMENTS

GENERAL

1. Group 14 consists of ve elements : c!"#$, %&'&c#$, ()!*$&+*, &$ $-')-.2. All the elements have the valence electronic conguration : $%2$2.3. Group 14 elements change from a typical $#$*)'(carbon) at the top ofthe group to a typical

*)'(lea) at the bottom. !ilicon an germanium are *)''#&-%havingsome properties of

metals an non"metals.4. #ariation of the physical properties of the group 14 elements.

$roperties carbon silicon germanium tin lea%lectronicconguration

1s22s22p2 &'e3s23p2 &Ar314s2

4p2&*r41+s2

+p2&,e4f14+1-s2

-p2

Atomicraius

ncreases/his atomic raius increases o0n the group ue to increase inscreening eect 0ith an increase in nuclear charge an theistance of the valence shell from the nucleus increases.

1stionisationenergy

ecreases/he ecrease in rst ionisation energy o0n the group is ue to theincrease in atomic raius as 0ell as the screening eect.ut the rst ionisation energy of lea is slightly higher than thatof tin. /his coul be ue to the less eective screening eect of the

electrons in the 4f orbitals.!tructure Giant covalent molecular Giant metallic lattice5eltingpoint

ecreases(i) /he melting points of carbon6 silicon an germanium are highsince the bons that nee to be bro7en are strong covalent bons.8o0ever6 the strength of the bons ecreases in the orer 9"9 !i"!i Ge"Ge as the atomic raius increases in the orer 9 ; !i ; Ge.8ence the melting points of the elements ecreases in the orer 9 !i Ge.(ii) /he metallic bons in tin an lea are 0ea7er than thecovalent bons. 8ence6 the melting points of tin an lea are lo0er.As the atomic raius of lea is larger than tin6 the metallic bon inlea shoul be 0ea7er than in tin. ut lea has a higher meltingpoint than tin because the lea atoms are pac7e more closely inthe metal lattice 0hile tin has a more open structure.

%lectrical9onuctivity

Graphite 2 an >4.2. /he o=iation state of >2 involves only the valence p electrons6 0hilethe o=iation state

of >4 involves both the valence s an p electrons.3. !ince the energy re?uire to remove all four valence electrons from anatom of a group

14 element is very high6 the >4 o=iation state is usually foun incovalent an not ionic

compouns of the elements.4. @n escening the group6 the >4 o=iation stater becomes less stablean the >2 state

becomes more stable. /his is a result of the inert pair eect 0hichbecomes stronger

o0n the group. /he inert pair eect arises from the non"involvementof a pair of

valence sB electrons in bon formation. (inert pair eect: for some big atoms li7e lea6there is a tenencynot to use the pair of

s valence electrons for bon formation).

Celative stability >4 state

!tability ecreases

!tability increases

>2 state

9 !i Ge !n $b

O&-)% # G!#+ 14 E')*)$%

1. Group 14 elements form the mono=ie 6 5@6 an the io=ie6 [email protected]. @n escening Group 14 (a) the boning of the o=ies changes from covalent to ionic. (b) the aci"base nature of the mono=ies (5@) changes fromneutral to amphoteric

0hile that of the io=ies (5@2) changes from aciic to

amphotericD

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3. Aci"base nature of o=ies an mono=ie:

M#$#&-)%

B#$-&$( Ac&-"%)$+!)

E+$%

9@ 9ovalent(simple

molecular)

'eutral

!i@ 9ovalent(simple

molecular)

'eutral

Ge@ onic"covalent Amphoteric Ge@(s)> 28>

(a?) Ge2>

(a?)>

82@(l)Ge@(s)> 2@8

"(a?) Ge@2

2"(a?)

> 82@(l)!n@ onic Amphoteric !n@(s)> 28

>(a?) !n

2>(a?)>

82@(l)

!n@(s)> 2@8"(a?) !n@22"(a?)> 82@(l)

$b@ ionic Amphoteric $b@(s)> 28>

(a?) $b2>

(a?)>

82@(l)$b@(s)> 2@8

"(a?) $b@2

2"(a?)

> 82@(l)&-)

9@2 9ovalent(simple

molecular)

Aciic 9@2(g)> 2@8"(a?) 9@3

2"(a?)>

82@(l)

!i@2 9ovalent(giant

molecular)

Aciic !i@2(s)> 2@8"(a?) !i@3

2"(a?)

> 82@(l)

Ge@2 9ovalent"ionic Amphoteric Ge@2(s)> 489l(a?) Ge9l4(l)>82@(l)Ge@2(s)> 2@8"(a?)> 282@(l)

Ge(@8)-2"(a?)!n@2 9ovalent"ionic Amphoteric !n@2(s)> 489l(a?) !n9l4(l)>

82@(l)!n@2(s)> 2@8"(a?)> 282@(l)

!n(@8)-2"(a?)

$b@2 9ovalent" ionic Amphoteric $b@2(s)> 489l(a?) $b9l4(l)> 82@(l)$b@2(s)> 2@8"(a?)> 282@(l)

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$b(@8)-2"

(a?)

5ono=ie : neutral amphoteric

io=ie : aciic amphoteric

4. T)!*' %"&'&5 # *#$#&-)% $- -&-)% # G!#+ 14 (a) /he *#$#&-)% # c!"#$, &$, ')-are )!*''5 %"')6 0hereasthe mono=ies of %&'&c#$

$- ()!*$&+* !) $#. 8o0ever 0hen ))- &$ &!6 9@ an !n@o=iiEe to 9@2an !n@2. (b) /he Group 14 -&-)% )c) P"O2!) '' )!*''5 %"')an aremore stable

than their mono=ies 0hich can be #&-&6)- to their #&-)%. (9) !ummary :5ono=ie 9@ !i@ Ge@ !n@ $b@/hermalstability

!table(reucing

agent)

Fnstable Fnstable(reucing

agent)

!table(reucing

agent)

5ost stable

io=ie 9@2 !i@2 Ge@2 !n@2 $b@2/hermalstability

!table even at high temperatures Fnstableecompose0hen heate.2$b@22$b@

>@2(o=iiEingagent)

C!"#$ -&-)%

1. our o=ies of carbon are 7no0n6 that are 9@6 9@26 93@2an 912@H. Among

them6 carbonmono=ie (9@) an carbon io=ie (9@2)6 are more 0ell 7no0n an are ?uietuseful in certain

aspects.2. 9arbon mono=ie6 9@6 is prouce 0hen carbon io=ie gas6 9@26 is passeover heate carbon

to be reuce to [email protected]@2(g) > 9(s) 29@(g)

/he gas can be also be prouce by reucing methanoic aci usingconcentrate sulphuric aci.

89@@8(l) 42. SOHconc 9@(g) > 82@(l) 8o0ever6 in a big scale inustrially6 carbon mono=ie is prouce bypassing steam over heate

co7e. A mi=ture of hyrogen an carbon mono=ie gases are prouce. /heen prouct is

calle 0ater gasB an is use as fuel.9(s) > 82@(l) 9@(g) > 82(g)

Iater gas

3. 9arbon mono=ie is a to=ic gas. 9hemically6 it is neutral an issolvespartially in 0ater. 9arbon

mono=ie can e=ists in three possible structures. /he main covalent bon inthe molecule is the

hybri orbital sp.

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All the structures of carbon mono=ie above sho0 that o=ygen atompossessing lone pair of

electrons. /hat is 0hy carbon mono=ie is a goo ligan. n a comple=consisting of transition

metals as the centre ion6 the carbon mono=ie molecules form ligans byonating a lone pair of

electrons through ative bons. /hese comple=es are 7no0n as carbonylcompouns. !ome

e=ample of carbonyl compouns are sho0n belo0 :

4. 9arbon mono=ie6 though thermally stable (oes not easily ecompose unerheat) is an

unstable molecule in air. t is reaily o=iise to 9@2in the presence ofo=ygen.

29@(g) > @2(g) 29@2(g)+. 9arbon io=ie6 9@26 is a colourless an oourless gas. Fnli7e carbon

mono=ie6 carbon io=ie is non"to=ic. t is slightly aciic an it forms non"polar linear molecule 0ith structure @ J 9 J ). /he main covalent bon is alsothe hybri orbital sp. /he intermolecular forces are 0ea7 van erIaals forces.9arbon io=ie has a lo0 boiling point an sublimes at lo0 temperatures. Atroom temperature an pressure6 carbon io=ie e=ists as a gas.

-. 9ommon use of carbon io=ie inclues the follo0ing : (a) 9arbon io=ie use in re e=tinguishers are store uner high pressure. !o6

0hen the gas is suenly release into the atmosphere6 suen e=pansion ancooling of the gas causes a ense layer of imKammable gas to form on top of theKame6 bloc7ing o o=ygen supply an thus halts burning.

(b) 9arbon io=ie is also use in ma7ing aerates rin7s an beverages an in themanufacture

of ba7ing soa6 'a89@3. (c) !oli 9@2or ry ice is use as refrigerant as 0ell as for proucing stage eectsB

as it sublimes immeiately to prouce a clouy an misty environment.S#*) I*#!$ R)c$% # O&-)% # L)-

1. Lello0 lea () o=ie ($b@) is stable to heat. Ihen heate strongly in air it forms relea ($b3@4) 0hich

reverts bac7 to lea () o=ie on further heating.-$b@(s) > @2(g) 2$b3@4

2. Mea () o=ie issolves in hot ilute nitric aci but not in ilute 89l or ilute 82!@4because the salts

forme ($b9l2an $b!@4) are insoluble.$b@(s) > 28'@3(a?) $b('@3)2(a?) > 82@(l)$b2>(a?) > 29l

"(a?) $b9l2(s) (0hite ppt)

$b2>(a?) > !@42"

(a?) $b!@4(s) (0hite ppt)

3. ro0n lea (#) o=ie ($b@2) ecomposes on heating to form yello0 lea () o=ie($b@) an o=ygen.

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$b@2is a po0erful o=iiEing agent.2$b@(s) 2$b@(s) > @2(g)

ro0n yello0

4. ro0n lea (#) o=ie ($b@2) oes not react 0ith nitric aci. t reacts 0ith colconcentrate hyrochloric

aci to form a yello0 li?ui of lea (#) chlorie6 0hich ecomposes slo0ly at roomtemperature to form a

0hite precipitate of lea () chlorie an chlorine gas. !o6 $b@2reacts 0ith hotconcentrate hyrochloric

aci to form a 0hite precipitate of lea () chlorie an chlorine gas is given o.Ihen col :$b@(s) > 489l(a?) $b9l4(l) > 282@(l)ro0n yello0 li?ui

At room temperature :$b9l4(l) $b9l2(s) > 9l2(g)yello0 li?ui 0hite ppt

8ot conc. 89l :$b@2(s) > 489l(a?) $b9l2(s) > 9l2(g) > 282@(l)

+. Ce $b3@4(triplumbum tetrao=ie) behaves in chemical reactions as if it is a mi=tureof 2$b@ an $b@2.

8ence6 0ith hot ilute nitric aci6 the $b@ part issolves to form a?ueous lea ()nitrate 0hile the $b@2

oes not6 resulting in a colourless solution 0ith a bro0n soli.

$b3@4(s) > 48'@3(a?) 2$b('@3)2(a?) > 282@(l) > $b@2(s) re soli bro0n soli

C'#!&-)% # G!#+ 14 E')*)$%

1. (a) Group 14 elements form ichlories of formula 59l2an tetrachlories offormula 59l4. (b) @n escening Group 146 the tetrachlories become less stable an theichlories become

more stable. (c) /he increasing stability of the ichlories (>2 o=iation state) is ue to

the increasing inertpair eect.

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2. /he tetrachlories are(a) simple non"polar covalent molecules 0ith a tetraheral shape.

(b) volatile li?uis at room temperature . their lo0 melting an boilingpoints are ue to the

0ea7 van er 0aals forces bet0een the molecules. (c) Generally6 the melting points an boiling points generally increaseso0n the group as the

siEe of the molecules increases.

3. /hermal stability of the tetrachlories (a) /he thermal stability of nthe tetrachlories ecreases o0n the groupue to the 0ea7ening

of the covalent 5 < 9l bon. /his is because on escening the group (i) the atomic raius of the element increasesD

(ii) the length of the 5 < 9l bon increasesD(iii) the 5 < 9l bon strength ecreases

(b) (i) 99l46 !i9l4 an Ge9l4o not ecompose onD even at hightemperatures. (ii) !n9l4ecomposes to tin () chlorie an chlorine gas 0hen heate: !n9l4(l) !n9l2(s) > 9l2(g) (iii) $b9l4is only stable at temperatures ; +9. t ecomposes at roomtemperature to lea () chlorie an chlorine :

$b9l4(l) $b9l2(s) > 9l2(g)

4. 8yrolysis of the tetrachlories

(a) All tetrachlories (e=cept 99l4) are easily hyrolyse by 0ater to form therespective o=iesaccompanie by the evolution of 0hite fumes of hyrogen chlorie.

59l4(l) > 282@(l) 5@2(s) > 489l(g) e.g. !i9l4(l) > 282@(l) !i@2(s) > 489l(g)

(b) /he mechanism of hyrolysis is !i9l4 6 Ge9l46 !n9l4 an $b9l4(represente by 59l4) is asfollo0s :

(i) /he 5 atom uses its empty valence orbitals shell to form

coorinate bons 0ith 0atermolecules.

59l4(l) > 282@(l)

(ii) /he octaheral comple= forme is not stable an ecomposes?uic7ly evolving hyrogen

chlorie.

5@2(s) > 489l(g)

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(c) /etrachloromethane (carbon tetrachlorie < 99l4) is not hyrolyseby 0ater because(i) the carbon atom oes not have orbitals in its valence shell

(no 2) to e=pan its octet. !o it cannot accept lone pairs ofelectrons from the o=ygen atoms in the 0ater molecules to

form coorinate bons.

(ii) /he big chlorine atoms surrouning the very small centralcarbon atom shiel its eectively from any attac7 by 0atermolecules.

7!)#$%1. reon are chloroKuorocarbon compouns (also 7no0n as 99Bs) that

can be obtaine from tetrachloromethane by substituting one or moreof the chlorine atoms by Kuorine atoms. /his can be one by reactingtetrachloromethane 0ith hyrogen Kuorie in the presence of acatalyst.

e.g. 99l4 > 8 99l3 > 89l

2. %=ample of freons are 99l36 929l2an 939l

3. reons are inert6 volatile6 non"to=ic6 non"corrosive6 non"inKammablean easily li?uee.

/here are use mainly as coolants in refrigerators an air > 2e Ge2> %P J " 1.- #!n4> > 2e !n2> %P J > .1+ #$b4> > 2e $b2> %P J > 1.O #

t can be euce that in a?ueous solutions :

(a) /he stability of the 52>ions ecreases in the orer Ge4> !n4> $b4>

(b) /he stability of the 52>ions increases in the orer Ge2>; !n2> ;$b2>

(c) n a?ueous solution !n2>is only slightly more stable than !n4>. !o!n2>can be o=iise by stronger o=iising agents li7e aciie*5n@4

() $b2>

is more stable than $b4>

3. As the inert pair eect is less signicant in the !n2>ion6 it can furtherlose t0o s electrons

to form !n4>. !o a?ueous solutions of !n2>ions can function as areucing agent 0hen

reacte 0ith the appropriate o=iising agent. or e=ample :!n2>(a?) > 2e3>(a?) !n4>(a?) > 2e2>(a?)

!n2>(a?) > 2(a?) !n4>(a?) > 2"(a?)

4. $b2> ion is more stable than the $b4>ion in a?ueous solution becausea more signicant

inert pair eect. esie6 the $b2>ion is larger an less highly chargethan $b4>ion. Iith

its lo0er charge ensity6 the $b2>ion has lo0er polarising po0er thanthe $b4>ion. !o6

the $b2>ion 0ill be more stable as it is not so easily hyrolyse by0ater.

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&8)!)$ T5) # S&'&c)%

1. $rimary structural unit silicates 0ith iscrete anions

(a) !imple silicate (b) $yrosilicate (c)9yclic silicates (i) 9ontains simple6 iscrete !i@44" (i) 9ontains iscrete !i2@N-" (i)9ontains iscrete !i3@H

-"

anions 0here the metal anions forme 0hen t0oanions forme 0hen

cations are surroune by !i@44"units lin7 by sharing

three !i@44"

units lin7the silicate anions. @ne o=ygen atom. together6 each !i@44"

(ii) %=ample : Eircon6 Qr!i@4 (ii) %=ampl7e : 9a25g!i2@N unitsharing t0o

o=ygen atomsforming

a ring structure. (ii) %mpirical

formula : !i@3

2"

(iii) %=ample :a/i!i3@H

2. 9hain !ilicates

/here are t0o main types of chain silicates : the pyro=enes6 0hich containsingle stran chains

an the amphiboles 0hich contain ouble"stran6 cross"lin7e chains. (a) $yro=enes (single chain) :

(i) 9omposition : (!i@3)n2n"

%mpirical formula : !i@32"

%ach !i@44"unit is lin7e to t0o other !i@44"units6 sharing t0oo=ygen atoms6 forming a

chain. (ii) %=ample : 5g!i@3

(/he empirical formula of the anion6 !i@32"in a pyro=ene is the sameas that in a silicate

0ith a cyclic anion 0here t0o o=ygen atoms for each !i@44"unitare share)

(b) Amphiboles (ouble chains) (i) 9omposition : (!i4@11)n-"

%mpirical formula : !i4@11-"

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/he tetraheral !i@44"units lin7 together6 alternately sharing t0oor three o=ygen

atoms6 that is every other unit in a single chain sharing a thiro=ygen atom 0ith an

aRoining chain. (ii) %=amples : /he asbestos minerals

(c) n both the pyro=enes an the amphiboles the silicate anion chains lieparallel an are

hel together by the cations 0hich lie bet0een them. /he !i"@ bonsin the chains are

very strong 0hereas the electrostatic forces bet0een the chains arerelatively 0ea7.

8ence these substances cleave reaily in irections parallel to thechains (asbestos is

brous6 a characteristic property of an amphibole).

(b) n the sheet silicates structures6 the sheets are bone 0ea7ly togetherby the cations

0hich lie bet0een them. 8ence such substances cleave reaily intothin sheets (Ka7y : a

property of mica). /he sheets also slie easily over one anotherma7ing silicates li7e talcum

soft an slippery.

(c) 9lay minerals are sheet silicates containing aluminium ions6 callehyrate

aluminosilicates. n aluminosilicates some of the silicon atoms aresubstitute by aluminium

atoms. 9lay is built fromtetraheral !i2@+2"sheets an octaheral

sheets consisting of unitsof Al3>ions surroune by si= o=ie or hyro=yl ions.

(i) n 7aolinite clay6 tetraheral sheets an octaheral sheets arearrange alternately. /his

is 1:1 clay. /he layers are hel close together by hyrogen bons. t

is iScult for 0ater

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to enter the space bet0een the layers6 so 7aolinite oes not e=pan0hen 0et.

tetraheral sheetoctaheral sheet

hyrogen bontetraheral sheetoctaheral sheet

(ii) n montmorillonite clay6 each octaheral sheet is san0iche

bet0een t0o tetraheralsheets. /his is a 2 : 1 clay. 'o hyrogen bon is present bet0een

the layers6 so 0atercan easily entrr the space bet0een the layers causing oit to

e=pan. (Ihen ry6 the clay0ill crac7).

tetraheral sheetoctaheral sheettetraheral sheet

tetraheral sheetoctaheral sheettetraheral sheet

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Group 14 periodic table