Noble gas-ppt-,inert gas, group 18 elements# inert gas # nobal gas xenon compound

group 18 explained completely

1. By; Rahul
Gjus & T
Hisar Haryana
NOBLE GASES

2. Where are the noble
gases?
The elements in group 0, on the right of the periodic
table, are called thenoble gases.
He
Rn
Xe
Kr
Ar
Ne
helium
neon
argon
krypton
xenon
radon

3. NOBLE GASES
Thegroupofnoblegasesisregardedaszerogroupof
theperiodictable.
Thesearegasesatordinarytemperatureanddonot
havechemicalreactivity.
Duetochemicalinertness,thesewerecalledinter
gases.
TheelementsHelium(He),Neon(Ne),Argon(Ar),
Krypton(Kr),Xenon(Xe)andRadon(Rn)comprisenoble
gases.

4. Atomic World:
Fast and Furious
3,000 miles per hour
1 mile/sec
Air (oxygen + nitrogen
1,000 miles per hour
7,000,000,000
collisions per second
Helium

5. Now-a-days,asnumberofcompoundsofthesegases,
particularlyofxenonandkryptonhavebeenprepared,
thisshowsthatthesegasesarenotcompletelyinert.
Theyarecallednoblegasesinsteadofinertgaseswhich
signifiesthatthesegaseshavesomereactivity.
Becauseofthelowabundanceofthesegasesonearth,
theyhavealsobeencalledraregases.

6. Mendeleefhadnotleftanyspaceforthe
noblegasesintheperiodicTable
Obviously,hecouldnotimaginethe
existenceofelementswhichhavealmost
nochemicalreactivity.

7. Ramsay,discovererofthesegases,proposedanew
groupfortheseelementsonthebasisoftheiratomic
massesandlackofchemicalreactivity.
Thisgroupiscalledzerogroupoftheperiodictable.The
zerogroupalsosuggestschemicalinertnessorzero
valency.

8. Beforethediscoveryofnoblegases,therewasasudden
changefromthemostelectronegativehalogens(onright
handside)tomostelectropositivealkalimetals(lefthand
side)intheperiodictable.
TheadditionofzerogroupbetweenVIIAgroupandIA
grouphassolvedthisanomaly.

9. The position of noble gases in the periodic table was later
on confirmed by Moseley who constructed the periodic
table on the basis of atomic numbers.
The values of atomic number of noble gases strongly suggest
that they should be placed after halogens and before
alkali metals

10. Element Outer
electronic
configuration
Vander
Wall's
radius
(Å)
First
IE
(kjmol
-1
)
m.pt.
(K)
b.pt.
(K)
∆H
fux
(kjmol
-1
)
∆H
vap
(kjmol
-1
)
He
Ne
Ar
Kr
Xe
Rn
1s2
2s
2
2p
6
3s
2
3p
6
4s
2
4p
6
5s
2
5p
6
6s
2
6p
6
-
1.31
1.74
1.89
2.10
2.15
2372
2080
1519
1351
1170
1037
-
24.4
83.6
116
161
200
4.2
27.1
87.3
120
166
211
0.02
0.33
1.18
1.64
2.3
2.9
0.08
1.77
6.5
9.0
12.6
16.4
Physical Properties
Noble gases

11. CHEMICAL INERTNESS OF NOBLE GASES
Chemical Inertness of these gases is supported by the
reasons:
i)The atoms have stable completely field electronic
shells
ii)They have high ionisation energies
iii)The noble have almost zero electron affinities.
Therefore, they do not have any tendency to gain, lose
or share electrons with other atoms.

12. Chemical properties of Nobel Gases
Theatomsofinertgaseshavesaturatedshells,therefore
theyarechemicallyinert.
Recentstudieshaveshownthatundercertainspecific
condition,theyenterintochemicalcombinationsandform
somerarechemicalcompounds.
Thespecificconditionsandthetypesofcompoundsformed
bythesegasesaredisusedbelow-

13. Under excited condition:-Sparking Helium at low
pressure in presence of mercury, tungsten etc. forms
compounds like HgHe
2, HgHe
10, WHe
2.
Helium compounds are also fromedin discharge
tubes like BiHe
2, FeHe, Pt
3He, PdHe. These compounds
are not considered as true chemical compounds as He
is absorbed on the surface .

14. •Compoundsformedthroughco-ordination-Argonformsa
numberofunstablecompoundwithvaryingno.ofBF
3
moleculese.g.Ar.BF
3,Ar.6BF
3
•Inthesecompounds,argonatomsdonatesapairof
electronstoBoronatomofBF
3.
•IncaseofhighercompoundsfluorineatomsofBF
3also
donatepairofelectrons.

15. c)Hydrates of noble gases:The hydrates of these gases
are formed by compressing the gases with water e.g.,
Xe.6 H
2O.
d)Compounds formed by physical trapping (Clathrates)
The inert gases Argon, Krypton and Xenon form solid
compounds with certain organic molecules such as
phenol and hydroquinone under pressure
In such compounds the inert gas are enclosed in the
crystal lattice of organic compounds known as
clathrates or cage compounds.

16. Xenonformsalargeno.ofcompoundswithoxygen
andfluorineindifferentoxidationstates.Theseare
xenonfluorides,xenonoxidesandxenonoxifluorides.
1.XeF
2
Preparation.
1.Xenondifluorideisbestpreparedbyheatinga
mixtureofxenonandfluorineinmolecularratioof
2:1at400
0
Cinasealednickeltube.Oncooling
quickly,acolourlesssolidXeF
2isobtained.
Ni
Xe+F
2 XeF
2
400
0
C
Compounds of noble gases-

17. Properties
1.Xenondifluorideisacolourless,crystallinesolid
whichmeltsat129
0
C.
2.Itreactswithhydrogentogivehydrogen
fluorideandxenon.
XeF
2+H
2 Xe+2HF

18. 3.Itgivessubstitutionreactionswithstrongprotonic
acids.
XeF
2+HX FXeX+HF
FXeX+HX XeX
2+HF
Where X=CIO
-
4CF
3COO
-
,SO
3F
-
etc.

19. 4.It hydrolyses slowly but completely in
acidic, neutral or alkaline solutions.
2 XeF
2+2H
2O 2 Xe+4HF+O
2
2 XeF
2+4NaOH 2Xe+4NaF+O
2+2H
2O
5.It oxidizes iodine in the presence of BF
3
to give IF.

20. 2.XeF
4
Preparation.
Itispreparedbyheatingamixtureofxenonand
fluorine,inanickelvassal,at400
0
Cunderpressure
of5-6atm.
Itcanalsobesynthesizedbypassinganelectric
dischargethroughamixtureofxenonandfluorineat
-78
O
C.
Properties of XeF
4are:
Itisacolorless,crystallinesolid,withm.pt.117.1
0
c,
sublimesreadily.
OxidizedbyhydrogentoHFat30
0
C.
AstrongerfluorinatingagentthanXeF
2

21. 3 . XeF
6
Preparation.
1.Itispreparedbyheatingxenonwithexcessoffluorine(inthe
molarratioof1:20)inanickelvesselat250-300
0
Cunder
pressureof50-60atm.
Xe+3F
2 XeF
6
2.ItcanalsobeobtainedbytheoxidationofXeF
4withO
2F
2under
pressure.
XeF
4+O
2F
2-130
0
cXeF
6+O
2

22. 2XeF
6+SiO
2 2XeOF
4 +SiF
4
2XeOF
4+SiO
2 2XeO
2F
2+SiF
4
2XeO
2F
2+SiO
2 2XeO
3+SiF
4
(explosive)
Properties:-Crystalline substance, m.pt. 49.5
0
C, Mostly
volatile, all the fluorides of xenon are greenish yellow
colour vapour . It is extremely reactive. Therefore, it cannot
be stored in glass or quartz vessels because of the
following reactions which finally give the dangerously
explosive xenon trioxide.

23. 2It reacts with fluoride ion acceptors to form adducts.
XeF
6+PtF
5 XeOF
4+PtF
5 [XeF
5]
+
[PtF
6]
-
XeF
6+SbF
5 XeF
6.SbF
5 [XeF
5]
+
[SbF
6]
-
XeF
6+AsF
5 XeF
6.AsF
5 [XeF
5]
+
[AsF
6]
-

24. 4.XeOF
4
Preparation:
(i)XenonOxytetraflourideispreparedbypartial
hydrolysisofXenonhexaflouride
XeF
6
+
H
2O XeOF
4+2HF
(ii)bytheactionofXeF
6onsilicondioxide
2XeF
6
+
SiO
2 XeOF
4+SiF
4

25. SoonastheyellowcolourofXeF
6disappears,the
contentsareimmediatelyquenchedwithsolidCO
2.Itis
donetoavoidtheformationofXeO
3(explosive)as:
XeOF
4+SiO
2 XeO
3+SiF
4

26. Properties.
1.Itisacolourlesscompoundmeltingat-46
o
C.
2Itisreducedbyhydrogentoxenon.
XeOF
4+3H
2 Xe+H
2O+4HF
3Itreactswithwaterorsilicatoformanotheroxyfluoride,
XeO
2F
2,in;whichxenonremainsinthesameoxidation
state.FurtherreactiongivesexplosivecompoundXeO
3

27. 4XeOF
4+H
2O XeO
2F
2+2HF
XeO
2F
2+H
2O XeO
3+2HF
2XeOF
4+SiO
2 2XeO
2F
2+SiF
4
2XeO
2F
2+SiO
2 2XeO
3+SiF
4

28. 5. XeO
2F
2
Preparation;
1.bymixingXeO
3andXeOF
4attemperaturecloseto-
78
O
C.
XeO
3+XeOF
4 2XeO
2F
2
Thecompoundispurifiedbyfractionaldistillation.
2.ItisalsoformedwhenXeOF
4ishydrolyzedor
reactedwithsilica.
2XeOF
4+SiO
2 2XeO
2F
2+SiF
4
XeOF
4+H
2O XeO
2F
2+2HF

29. Properties.
1.Itisacolourlesssolid.
2.Itsmeltingpointis30.8
O
C.
3.Itiseasilyhydrolyzedtogivexenontrioxide.
XeO
2F
2+H
2O XeO
3+2HF.

30. 6.XeO
3
Preparation.
Xenon trioxide is prepared by the hydrolysis of XeF
6or XeF
4
6XeF
4 + 12H
2O 2XeO
3 + 4Xe +24HF+3O
2
XeF
6+3H
2O XeO
3+6HF
Itactsasapowerfuloxidizingagentinacidicmedium.For
instance,itoxidizesPu
3+
toPu
4+
inthepresenceofH
+
ions.
6Pu
+3
+XeO
3+6H
+
6Pu
+4
+Xe+3H
2O

31. 7. XeO
4
Preparation:-
Itispreparedbyactionofconc.H
2SO
4onsodiumor
bariumxenate(Na
4XeO
6orBa
2XeO
6)atroomtemp.
Na
4XeO
6+2H
2SO
4 XeO
4+2Na
2SO
4+2H
2O
Properties:
Itisveryunstableanddecomposestoxenonandoxygen.

32. Structure of Some Xenon Compounds
FormulaName Oxid
n
state
m.pt. (
o
C)Structure
XeF
2
Xenon
difluoride
+2 129 Linear
XeF
4
Xenon tetra
fluoride
+4 117 Square Planner
XeF
6
Xenon
hexafluoride
+6 49.6 Distorted octahedron
XeO
3
Xenon
trioxide
+6 Explodes
Pyramidal tetrahedral with
one corner un occupied

33. XeO
2F
2 Xenon dioxy
difluoride
+630.8Trigonallipyramid
(with one position
unoccupied)
XeOF
4 Xenon oxy
tetrafluoride
+6-46Square pyramidal
(octahedral with one
position un occupied
XeO
4 Xenon tetra
oxide
+8-35.9Tetrahedral
XeO
3F
2 Xenon trioxy
difluoride
+8-54.1Trigonalbipyramidal
Ba
2[XeO
6]-4Barium
perxenate
+8 octahedral

34. Structure and Bonding in Xenon Compounds
FormulaStructure No.
of e
pairs
No. of
lone
pairs
VSEPR
(Explanation of structure)
XeF
2 Linear 5 3 Fiveelectronpairsformtrigonal
bipyramidalwiththreelonepairsat
equatorialpositions
XeF
4 Square
Planner
6 2 Sixelectronpairsformoctahedronwith
twopositionsoccupiedbylonepairs
XeF
6 Distorted
octahedron
7 1 Pentagonalbipyramidalorcapped
octahedronwithonelonepair
XeO
3 Pyramidal7 1 Threeπbondssothattheremainingfour
electronpairsformatetrahedronwith
onecorneroccupiedbyalonepairs.

35. Formula Structure No. of
e
pairs
No. of
lone
pairs
VSEPR
(Explanation of structure)
XeO
2F
2 Trigonal
lipyramid
7 1 Twoπbondssoremainingfive
electronpairformtrigonal
bipyramidwithoneequatorial
positionoccupiedbyalonepair
XeOF
4 Square
pyramidal
7 1 Oneπbondsoremainingsix
electron pairs form an
octahedronwithoneposition
occupiedbyalonepair.
XeO
4 Tetrahedra
l
8 0 Fourπbondssoremainingfour
electronpairformatetrahedron
XeO
3F
2 Trigonal
bipyramid
8 0 Threeπbondssoremainingfive
electronpairsformtrigonal
bipyramid
Ba
2[XeO
6] Octahedral 8 0 Twoπbondssoremainingsix
electronpairformanoctahedron.

36. . .
Xe
. .
XeF
4 sp
3
d
2
Xe
F
.
.
F
.
.
Molecule Type of Hybridization
Geometrical Shape
XeF
2
F
F
F F

37. XeF
6 sp
3
d
3
. .
Xe
xe
XeO
3 sp
3
F
F
F
F
F
F
Geometrical Shape
Molecules & Type of hybridization

38. xe
O
F
O
XeOF
4 sp
3
d
2
Xe
F
XeO
2F
2 sp
3
d
O
F F
F
F
. .
. .
F
XeO
2F
4 Sp
3
d
2
Xe
O
F F
F
F
O

39. XeOF
4 Sp
3
d
2
Xe
O
F F
F
O
XeO
6 Sp
3
d
2
Xe
O O
O
F
O
-4
-4
O
. .

40. SignificanceofNoblegasesindevelopmentof
theoreticalchemistry.
1.InElucidationofdistributionofelectronsinatom
2.Inperiodicclassification
3.Inthedevelopmentofelectronictheoryofvalency
4.Inradioactivity.

41. Thank you