Inorganic Chemistry for JEE (Advanced) [2, 3 ed.] 9353503833, 9789353503833

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p-Block Group 18 Elements The Inert Family

5

OVERVIEW 1. Group 18 elements comprise helium (He), neon (Ne), argon (Ar). krypton (Kr), xenon (Xe) and radon (Rn).

lattices of certain organic and inorganic compounds. These combinations are called cage compounds or clathrate compounds or enclosure. The crystal structure with cavities is called the 'Host' and the atom or molecule entrapped in it is called the 'Guest'. These are non-stoichiometric compounds, e.g., Xe-6H,0, quinol clathrate. He and Ne do not form clathrate compounds as the size of the cavity is more than the size of the He or Ne atom.

, Group 18 elements are alsO known as inert gases, rare gases, noble gases, zerovalent elements or aerogens. However, the names inert gases and rare gases are misnomers.

3. General electronic configuration of group 18 elements is ns np, except He, whose electronic configuration is 1s2. 4. Argon is the most abundant noble gas, about 1% by volume in air. It is nearly 30 times more abundant than CO, (0.03).

In the universe, the order of abundance is He> Ne>Ar>

13. Only He forms interstitial compounds with metals.

14. Solution of XeF in HF is conducting due to formation of ions.

Kr> Xe.

5. a. Ionisation enthalpy: He > Ne > Ar> Kr> Xe > Rn

15.

b. Melting point: Rn> Xe> Kr> Ar> Ne> He

Discovery of noble gases Helium Lockyer and Janssen

c.

Neon

:Ramsay and Travers

Argon Krypton

:Lord Rayleigh and Ramsay

Boiling point: Rn > Xe> Kr >Ar> Ne > He

d. Ease of liquefaction: Xe > Kr > Ar> Ne> He 6. Helium can be diffused through rubber, glass or plastics. . Noble gases are monoatomic, colourless, odourless, tasteless, sparingly soluble in H,O have low melting and boiling points due to weak van der Waals forces of attraction between the noble gas atoms. 8. True compounds of He, Ne and Ar are yet not discovered. 9. Most of the compounds of noble gases involve only fluorine and oxygen. This is due to the fact that any chemical

reactivity shown by noble gases may be attributed to their tendency to lose electrons. For this reason, the combining atoms must be highly electronegative such as F (EN 4.0) and O (EN 3.5). =

The only compound of Kr studied in detail is KrF%. Ke in its compounds exhibits even oxidation states from +2 0.

Xenon

:Ramsay and Travers :Ramsay and Travers

Radon

:Dorn

16. On passing electric discharge through noble gases at low pressure (2 mmHg). the gas starts glowing with a

characteristic colour. This phenomenon is used in glow signs also called neon signs. The colour also depends upon the pressure of the gas. Colour of

Noble

Pressure

gasused

Red

ofthe gas

Neon

10-18 mm

White

Helium

34 mm

Light blue

Argon-Neon

10-20 mm

glow

to +8.

mixture +Hg

Oxidation state

Compound

+2

+4

XeF2

XeF

+6

XeF

+8

XeO

Ae also shows an oxidation state of +8 in perxenates,

AeO]. Perxenates are strong oxidising agent_and

oxidises CI°>Cl, H,O

CeS

Ce*.

4.Clathrates: n

O,, Mn"

MnOand

Noble gases form a number of combinations which gases are trapped into the cavities of crystal

vapours The colour can also be modified

for the discharged tube. 17. Neon is

by the use of coloured glass

widely used in neon signs which are used for advertising purposes in the form of brilliant orange-red glow. This colour is changed by mixing argon and mercury vapours with neon to light blue. Since the light of neon signs has better penetrating power through fog and mist so these are used in beacon lights for safety of air navigations.

5.2

Inorganic Chemistry

18. Neon lamps are used in botanical gardens and the green houses as these stimulates growth and are effective in the

formation of chlorophyll. 19.

creating inert atnmosphere in chemical Argon for reactions, welding and metallurgical operations and also used filling in incandescent and fluorescent lamps. It is tubes. thermionic in filling Geiger-Counter tubes and is used for

20.

on-85 clathrate provides B-radiations which are

a

safe and

useful for

measur

gauges.

useful souce

thickness q

21. Krypton and Xenon are also used in gas-fi

However, these gases

are

super

to

argon but

lamp

costly. A mixture of krypton and xenon is alsoua ; Y flash tubes for high speed photography. Radon i radioactive research and therapeutics and in the treatment

of cancer

and other

non.

malignant growths

The kry fama have

or

are becs attra

disc

ho the

0.9 rarc SOL a

p-Block Group 18 Elements: The Inert Family

CENERALIN INTRODUCTION amic gases, helium (He), neon (Ne), argon (Ar), venon (Xe) and radon

Element Sym- Year of

(Rn) constitute

Name of

bol discovery discoverer

monoa.

Helium He

separate I8 clements. These elements a

ploelements known as group lyalled as inert gases, rare gases, aerogens, noble gases raelements. The names inert gases and rare gases ers, Initially these gascs were referred as inert gases

1895

goup

| Janssen

s n emusnonmers,

1Sheir chemical inertness. Their inertness was generally their very stable electronic to their configurations. With the

Ne

1898

|Ar

1894

vo

covery

of large number

of xenon compounds

in 1962, it

Argon

was

hiscat Xenon is not inert and hence the name inert gases is a These gases werealso referred as rare gases because of

sively uncommon existence on earth, but argon constitutes tive

th

rare.

Sir William From the Greck Ramsay and word, 'neos' which means 'new' Travers

Lord

From the Greek

Ramsay

mIsnomer:

09%by

word, 'helios'

Rayleigh and 'argos' which Sir William means inactive'

shownthat

rel

of name

which means 'sun Ncon

.

tributed

Origin

|Lockyer and From the Greek

"becn

r

|Krypton Kr

olume of the afmospliere and thus these gases are not

1898

cept Rn, all these gases occur in atmosphere and thus are

Sir William From the Greek Ramsay and word, 'kryptos

Travers

which means hidden'

Sir William

From the Greek

Éxcep

Ted to as aerogens. Nowadays, they are called times refere as to convey the impression that these gases do gases so Some reactivity, Just like noble metals such as gold and

Xenon

1898

Xe

Ramsay and

noble

have

dlstinum. which are often reluctant to react and yet are not totally

Radon

Rctive. These elements are also known as zerovalent elements unreac.

1898

Rn

word xenos' which

Travers

means 'stranger

Friedrich

Named after the element 'radium. Radon, was called nitron at first from

Ernst Dorn

thev show zero valency due to their chemical inertness.

Consequently the group to which these elements belong is also moWn as zero group and these elements are known as group

the latin word

zero elements.

nitens' meaning

Julius Thomson justified the position of noble gases in the periodie table by giving argument that since there are highly electropositive elements (alkali metals) on extreme left and

'shining

5.2 OCCURRENCEAND ABUNDANCE in free

elements (halogens) on extreme right of must be a group of elements which there the periodic table should form a bridge between highly electropositive and highly

highly electronegative

On account of their inert nature, noble gases

so

were

always occur

in free state as it state. Radon, being radioactive does not occur life of less than half has decays rapidly. Its longest lived isotope four days. The chief sources of noble gases are: Kr and Xe in dry Atmosphere: The total abundance of He, Ne. Ar, the is Ar which major component. volume of air is about 1%

electronegative elements, whrch should neither be electropositive that is why they are also nor be electronegative, i.e. zero valency, elements. knownasgroup zero Sir William Ramsay and Lord Rayleigh

5.3

awarded the

by

noble prizes in 1904 for their discovery of noble gases.

Table 5.1 Atomic and

physical properties of group

Property

Neon

Argon

Krypton

Xenon

Ne

Ar

Kr

Xe

Rn

He

18

36

54

S6

10

39.15

83.80

131.30

222.00

20.18

Atomic number 4.00

[He]2s 2p°

Electronic configuration

Atomic radii (pm) lonisation enthalpy (kJ mol)

190

200

220

1520

1170

1037

2080

1351

2372

96

68

96

77

116

3.7 x 10

5,9 x 10

9.7 x 10

4.2

Boiling point (K)

"Radioactive.

3s3p|[Ar] 344s6p*| [Kr]4dss spXe]4/*saas

160

Melting point (K)

(% volume)

[Ne]

120

tlectron gain enthalpy (kJ mol)| 48 1.8x 10 Density (at STP) (g cmn)

Enthalpy of vapourisation (kJ mol ) Abundance in atmospheric

Radon

Helium

Symbol Atomic mass (g mol")

18 elements

0.09

5.4

x

10|

9.0x 10

1.8 x 10 83.8

115.9

161.3

202.0

24.6

87.2

119.7

165.0

211.0

27.1 1.77

9.0

12.6

16.4

6.5

1.14 x 10

8.7 x 100

18

x

10

0.934

6p

5.4

Inorganic Chemistry Down the group (), 1.e. their melting and hoil. due to increase in the

5.3 ATOMIC AND PHYSICAL

PROPERTIES

Some of the atomic and physical constants of the noble gases have been summarised in Table 5.1.

5.3.1 MoNOATOMIC NATURE monoatomic All the 18 group elenments are colourless, odourless, valence stable ns'np° gases. as all the noble gases have is ls. electronie contiguration, except He whose configuration facts : the following Their monoatomie nature is supported by and 1. The ratio of their specific heat at constant pressure

shell

constant volume, i.e. C,C, » 1.66. 2. At STP, 22.4 L

ofeach gas weighs equal to the

poim magnitude of van iling er Waa

increase

forces of attraction with the increase in the atomic si:

atomic

mass

of the gas in grams. inert behaviour. Their monoatomic nature confirms their molecules because they do not They do not form diatomic He has the usual property of possess any unpaired electron. materials most commonly used laboratory

diffusing through

such as rubber, glass or plastic.

small difference in melting and boiling point indicate are casily vapouriscd so that they remain gases at the

The ver

that soid

at the temperatute

at which most of other elements are liquids or solids,

Helium has the lowest boiling point of any know substa 4.2 K Gascous He on cooling below ondenses to a liquid kno on cooling to 2.2 K at 1atm as Helium-I, which essure into a remarkable liquid known as Heli um-1I.

change Helium-II exhibu

the following properties: .High hcat conductance, 1.e. 600 times that of Cu:

temperature. Low viscosity i.e. 1/1000 th ofH, gas. Thus it is vim

Virtual

frictionless.

I t is also able to flow uphill. 5.3.6 ENTHALPY OF VAPOURISATION It gives a measure of energy required to overcome the forc of attraction between noble gas atoms. The forces of attractios between the noble gas atoms are van der Waals forces which

5.3.2 ATOMIC RADII The atomic radii of the noble gases are the largest in their respective in case of noble gases the radii is van der The reason

very weak and arises due to instantaneous dipole-induced dipoje

interaction Waals radii due to instantaneous dipole-induced dipole it other in whereas noble groups is covalent gas atoms; amongst the radii. In case of noble gases, covalent radii cannot be determined

and therefore van der Waals forces increase. Hence enthalpy

periods.

being

Down the group (). instantaneous dipole-induced droit increases or polarisability increases, with increase in atomic siz vapourisation increases. Enthalpy of vapourisation: He < Ne < Ar < Kr < Xe < Rn

as they can be solidified at very low temperature only and at such

low temperature X-ray crystallography cannot be performed. Down the group (), i.e. fromn He to Rn, the atomic radii increases primarily because at each successive step new shells

are being added and the electron cloud is expanding. Atomic radii: He < Ne < Ar < Kr < Xe

5.3.3 lONISATION ENTHALPY The ionisation enthalpies of noble gases are the highest as compared to ionisation enthalpies of other members in the same period due to the stable electronic configurations.

Down the group (), i.e. from the He to Rn, ionisation enthalpy decreases because of increase in atomic radii (size effect) and screening effect of the inner electrons.

lonisation enthalpy: He> Ne>Ar> Kr> Xe> Rn

5.3.4 ELECTRON GAIN ENTHALPY The electron gain enthalpy of noble gases is positive, as noble gases

have completely filled subshells. Hence, the additional electron has to be placed in an orbital of next higher shell. Consequently,

energy has to be supplicd to add an additional electron and hence, the electron gain enthalpy of noble gases is positive. Down the group (4), i.e. from He to Rn, as the size of the atom increases, electron gain enthalpies become less positive.

5.3.7 EASE OF LIQUEFACTION It is relatively difficult to liquefy noble gases due to weak vm der Waals forces of attraction between the atoms.

It is only the weak van der Waals forces (London dispersin forces) which are responsible for the liquefaction of these s Down the group (), with the increase in atomic size. n

of van der Waals forces of attraction increases an hence ease of liquefaction increases. Ease of vapourisation: He < Ne < Ar < Kr< Xe

magnitude

5.3.8 SoLUBILITY IN WATER Noble gases have relatively high solubility in water, i.e.solu of Ar in H,0 is greater than that of O, or wlc Down the group (), i.e. from He to Rn. solubility in increases.

N

Noble gases are soluble in water due to dipole-induced a interaction. Water is a polar molecule. Due to dipole in H,U, stortion induced dipole is created in noble gas atoms, due to dist or polarisation of otherwise symmetrical electron cloua o gas atom (Figure 5.1). Polar water

Symnetrical

molecule

electron cloud

HO*

5.3.5 MELTING AND BoILING POINTS The melting and boiling points of noble gases are extremely low in comparison to those substances of comparable atomic and molecular mass. This is because there is no strong interatomic forces. Only weak van der Waals forces operate which hold atoms together in liquid and solid state.

HÖ

O

O Polarised

electron cloud

Fig. 5.1 Polarisation of Xe atom by H,0 molecule

p-Block Group 18 Elements: The Inert Family 5.5 t h e group (), the atomic size increases and the

The smaller noble gases, He and Ne, do not form clathrate compounds because the noble gas atoms are small enough to escape through the cavities.

Down

oction of the electron cloud to its nucleus decreases and esults in greater distortion of their electron cloud by the

ning water molecule. The magnitude of dipole-induced

2. Noble gas hydrates: These are clathrate compounds but more commonly are referred to as noble gas hydrates. The noble gases Ar, Kr and Xe are trapped in the cavities formed when water is frozen under high pressure of gas. Their composition is approximately 6H,O 1 noble gas atom.

polaris

n dipoleinteraction

increases with the increasing size of the noble 0uand consequently, their solubility in water increases down

thegroup (4). Solubility in water: He < Ne < Ar < Kr < Xe

He and Ne do not form hydrates as they are too small as

5.4CLATHRATE COMPOUNDS

compared to the size of the cavity and thus escape through

clathrate compounds are also known as cage compounds or

the cavities.

hsion compounds. According to Powell, in the clathrates, atoms

Uses:

r molecules (krnown as guests) of appropriate size are trapped in

a. Clathrate compounds provide a convenient means of storage and transportation of radioactive isotopes of Kr and Xe produced in nuclear reactors.

the cavities of crystal latice ofother compounds (known as host). Though the gases are trappo they do not form true chemical bond. The only type of interaction in these compounds is the weak van Her Waals forces. Clathrates are normally non-stoichiometric

b. Clathrates play an important role in the separation of noble gases. For example, neon can be separated from

compounds. 1hey are not true chemical compounds.

argon, krypton and xenon by forming clathrates with

Essential conditions for clathrate compounds:

quinol because neon is the only gas that does not form

1. Presence of cavities of appropriate size in the crystal lattice

such clathrates with quinol.

of the host.

c. Clathrates play an important role in some physiological actions, e.g., it is thought that the anaesthetic action of xenon is due to aqueous clathrate formation in physiologically strategic spots. When the anaesthetic

2. Size of the guest atom/molecule should be such as to fit in

the cavities of the host without bringing any atoms closer together than which corresponds to van der Waals radii of the atom.

is no longer administered the clathrates equilibrium

is destroyed, the clathrates decompose and the

Stability of the clathrate compounds:

consciousness returns.

Clathrate compounds once formed are extremely stable because:

1. The guest molecule/atom fits tightly in the cavities of host molecule.

2. The guest molecules within the cages are at minimum

potential energy. Guest molecules can escape the host only when the forces holding the molecular cages together are overcome. This can be achieved by following two methods:

5.5INTERSTITIAL COMPOUNDS Interstitial compounds are formed when small atoms occupy the interstitial space of the metal lattice. Only He forms interstitial compounds since the atomic size of He is the smallest amongst the noble gases and matches the size of the interstices available in the lattice of most of the heavy metals.

5.6 CHEMISTRY OF NOBLE GASs COMPOUNDS

a. By heating the clathrate compound. b. By dissolving the clathrate compound in suitable solvent

such as alcohol.

The first noble gas compound was made in 1962. Bartlett and Lohman had used highly oxidising compound platinum

hexafluoride, PtF, to oxidise dioxygen, O,.

Types of clathrates:

PIF+O

1. Quinol elathrates: When an aqueous solution of quinol

(ie. 1,4-dihydroxy benzene. HO

OOH)

(red) Dioxygenyl hexafuoridoplatinate(V) Since first ionisation

S Crystallised under a pressure of 10-40 atm. of Ar, Kr

O2e

Or Xe, the noble gas atoms get trapped in the cavities of

Xe

4

A in the B-quinol structure. The composition of these

Clathrates correspond to 3 quinol: I noble gas atom, though

normally all cavities are not filled. When the quinol clathrate is heated or dissolved in solvent, ne hydrogen bonded arrangement of B-quinol breaks and

noble gas escapes.

0,° PIF,1° enthalpy of 0, and Xe are almost same, 0ete1175 kJ mol

Xete1170 kJ mol

it was predicted that Xe should also react with PtFs It was experimentally shown that when deep red vapours of PtF were mixed with equal volume of Xe, the gases combined immediately to

give yellow solid. It was (incorrectly) thought that the product

is Xe"[PtF [Xenon hexafluoridoplatinate(V)]. The reaction has since been found to be more complicated, and the product is

XeF) [PF,

5.6

Inorganic Chemistry

X [PtF1

Ps+Xe

Melting point decreases on moving from XeF .

[XeF]°[PtF,

XeF, which is contrary to the usual trend. Thio

(red)

Decp red

increase in polarity as the number of F-atome

vapours

yellow solid

react at 400°C to give Soon after this, it was found that Xe and F, this discovery, there colourless volatile solid XeF. Following of noble gases, in particular was rapid extension of the chenmistry

Helium,

neon

enthalpy

as

G) 2XeF,(s) + 2H,O()->2Xe(g) + 4HF(ag) + o +6

4

(ii) 6XeF+ 12H,0

compared

6

(i) XeF

lonisation enthalpy of Kr is little lower and it forms KrF.

XeO, +

+3H,0

XeOF, +2HF Xe0,F2 + 4HF

) XeF, +H,0 (ii) XeF+ 2H,0

compounds only with the most electronegative elements, i.e., F (EN =4.0), O (EN 3.5) or with highly electronegative groups such as OSeFs, OTeFs Xenon forms stable

Note: Hydrolysis reaction is a non-redox reaction, singe

=

the hydrolysis are XeOF, and Xe0F where the Os of all elements remain same as it was in reacting state

that contain both oxygen and fuorine.

of all the noble gases, Xe forms the largest number of

3. As fluorinating agent: All xenon fluorides act as strone

compounds. This may be attributed to its low ionisation

fluorinating agents.

enthalpy.

XeF 2 XeF, +2H,C = CH,

5.6.1 FLUORIDES OF XENON Xenon reacts directly with fluorine to give binary fluorides:

3. Kenon

difluoride, XeF

XeF +2SF

hexafluoride, XeF,

1. By heating Xe and F, at 400°C in a sealed nickel vessel. The products formed depends on Xe : F, ratio.

XeF2

373K603

Xe +6NH,F +N,

XeF +6HCI

6HF + Xe +3Cl,

an

oxidising agent:

XeF: Oxidises Ci°> Cl, 9 I , ete. XeF, +2HCI

good for XeF, because it readily experimental conditions to give

XeF,

+2KI

Properties: 1. XeF2, XeF, and XeF, are colourless crystalline solids and sublime readily at 298K. They are powerful fluorinating agents. They are readily hydrolysed even by traces of water.

+

l,

2Ce(So,),

XeF +2Hg

Xe +2HgF,

XeF+2KI

4KF+ Xe +21

XeF + 4HCI

+Xe+

XeF, + 3Hg

XeF, 117

XeF 49.5

4KF + Xe +2Cl,

XeF

2. Melting point:

Meltingpoint (°C)| 140

2KF +Xe

XeF

XeF, + O2

XeF

2HF + Xe +Cl,

XeF, +Ce" (SO), + SO

XeF. XeF, can be prepared by the interaction of XeF, and 0,F at 143k.

Xenon fluoride

+

XeF, +8NH, 4. As

1:5Xef4

Xe +F2873K.Tbar

2SF+Xe

PtF Xe XeF XeF +2C,H, 2C,H,F+2HF+Xe XeFs

Preparation:

+ Pt

XeF, +0,F2

CsH,F + Xe+HF

XeF

XeF

The method is not very reacts further under the

FH,C - CH,F +F,CHCH,

2Xe XeF, + CgH,

673K.1bar

6HF

Partial hydrolysis of XeF

radon identified by radiotracer technique

is RnF

1. Xenon

4Xe + 2Xe0, +24HF +30

F6

compounds are not fomed.

2. Xenon tetrafuoride,

As the

Hydrolysis: XcF2, XcF, and XeF

ionisation and argon have much higherfirst similar hence to xenon, and

Only compounds of

F.

Xe-atom increases.

XeFT°[PtF

of xenon.

due to

bonded to F-atoms bonded to Xe increases, there is more.number of accumulation of +ve charge on Xe, which decreand more decreases the stability of the molecule.

PIF60°C

5.

Xe +3HgF

Formation of addition

compounds:

forns

Xer, acts as fluoride ion donor (Lewis base) and

complexes with covalent pentafluorides including Pt,

p-Block Group 18 Elements: The Inert Family 5.7 xenate ion, [HXeO,] (oxidation state of Xe = +6) disproportionates slowly in solution to give and xenon. perxenates, [Xe0,] (oxidation state of Xe +8)

chE, and the transition metal fluorides, NbF, TaFs, RuFg, OsF

Hydrogen

RbF5, IrF', and PtF, (Lewis acids). These are thought

tohave the following

structure

Lewis base+ Lewis acid

XcF

(oxidation state o f Xe =

Adduct

[XeF]° [PF °

PFs

+

=

(+8)

(+6)

xeF, acts as fluoride ion donor (Lewis base) and forms few

[HXeO1+20H- >[X«O,]*+Ke +0 +2H,0 Perxentate ion

complexes with PF5, AsF% and SbF ewis acid

Lewis base

XeF +SbF

XeF

has

Adduct

oxidising agents. e. With

structure.

XeF+SbF b.

or [XeF

XeF,1° (SbF1°

XeF+2NOF

Ba[XeO,]+2H,SO

[NO],° [XeF]

Xe04+2BaSO +2H,0

Properties:

XeO

+Cs, [XeF,*

is

not

as

stable

as

Xe0,

and decomposes

give

Xe +20,

Reaction of perxenate ion [XeO,] with Mn* in acidic medium:

Xenon forms two oxides: (i) xenon trioxide, XeO, and (ii) xenon

etraoxide, XeO4

(i) 4H,O + Mn

MnO,°+Se +8H

(ii) 6H®+2e +[Xe0

XeOD,

Xe0, +3H,O

Multiply eq. (i) by 2 and eq. (i) by 5 and add them. Net equationis

Preparation: By complete hydrolysis of XeF by atmospheric moisture (slow

(2Mn2+14H®+5[XeO,]

2Mn0,° +SXeO +7H,0

I ion in acidic medium XeO, +91+6H. Xe +3H,O+31

iii) Reaction of XeO, with

reaction)

XeF +6H,0

(i)

XeO, +6HF

i) XeO, +61 +6H

Properties:

Xe +3H,0 +31,

a. White hyroscopic and highly explosive solid.

5.6.3 XENON OXYFLUORIDES

D. Acts as strong oxidising agent. It oxidises Pu" to Pu"" in

Xenon forms a number of oxyfluorides such as:

the presence of H" ions. 3Pu+ XeO, + 6H® c.

to

Xe and O

XeO

5.6.2 XENON OXIDES

L. Xenon trioxide,

2. Xenon tetraoxide, Xe0

Ba,[XeO,].

[XeF,1°

50°C XeF,

2XeO,F2

By the action of anhydrous or conc. H,SO, on barium perxenate,

On heating. [XeF,] decomposes as follows: 2Cs [XeF]

salt, M[Xe0,F] is obtained.

Preparation:

R b " XcF,]

XeF, + CsF. >Cs

solution of XeO, is treated with

Cs°[Xe0,Fj°

XeO, + XeOF

1° [AsF19

As fiuoride ion acceptor

XeF + RbF

a

f. With XeOF

NeF,+BFs[XeF^]"[BF,° AsF

When

oxo-fluoro

an

CsF +KF

As fluoride ion donor

XeF,

or CsF:

XeO KF >K®[Xe0,F

fuoride ion acceptor (Lewis acid).

NeF,+AsFs

KF

KF or CsF,

XeF acts both as fluoride ion donor (Lewis base) and as

a.

xenon

Solution of perxentates are yellow and act as powerful

> [XeF,° [sbF,1° T-shaped

0)

Reaction

with

3Pu" + Xe + 3H,O

XeF

XeO, +XeF,

3XeOF + XeO ion, [HXeO.

or XeO + ÕH

XeOf4

Xenon oxytetrafluoride

XeO,F

Xenon trioxydifluoride Xenon oxydifluoride

i. Partial hydrolysis of XeF, gives XeOF,

2Xe0,F2

AeO When pH> 10.5 (alkaline Xeo +NaOH

Xenon dioxydifluoride

XeOF

3XeOF4

In solution, is soluble in water, but does not ionise. forms hydrogen xenate medium) it

(+6)

Xe0,F2

(+6)

Na [HXeOJ [HXeO1 H y d r o g e n x e n a t e ion

XeF

+

H,0

XeOF, +

2HF

ii. Partial hydrolysis of XeF, gives oxyfluorides, XeOF, and

Xe0,F2 XeF + H0 XeF,+2H,0

XeOF, +

2HF

XeO,F2 +4HF

Properties of XeOF a. Clear, colourless mobile liquid which can be stored unchanged in Ni containers for long period.

5.8 Inorganic Chemistry b. Eight small sized F atoms can not accomodate.

b. With H,: Xe

XeOF, +3H, c. With silica: XeF +SiO,

+

H,O

sized Xe atom. This is called steric Thus XeFg is not formed.

+4HF

crowding

c. This is due to the fact that Ne is capable of

of carryin

extremely high current under high voltage.

SiF + XeO,

d. This is because Ne light is visible from long distan even visible during fog and mist conditions.

distances and

ILLUSTRATION S.1

e. This is due to the fact that at high pressure N, 2as

Explain:

a. Why does Xe not form fluorides such as XeF, XeFz and

soluble in blood as compared to He and when

highly

comes out of the sea a sudden change in pressure .

XeF?

degassing and releases bubble of

b. Xe shows +8 O.S. e.g., in XeO, but XcF, is not formed. C.

effect or ligand one large

N,

gas in

blood This

painful condition called "bends" or caisson

Why?

causes

Neon is used in safety devices for protecting electrical

He is slightly soluble so risk of bends is reduced

ickness

instruments?

ILLUSTRATION 5.2

d. Neon is used in waming signal illumination. e.

Why in deep sea diving a

mixture of (He +0,)

is used rather

Give the important characteristics of Helium (I).

than (Xe + N,) why?

Sol. Liquid helium is unique in that it exists in two

Sol a. e

ms He

I and He (liquid helium is obtained by Joule-Thomson expata ofthe gas previously cooled to 15 K which is below the inveni

=5s sp

temperature of He i.e., 35 K). The liquid helium I boils at 42{

Sp

and has nomal liquid properties. On cooling He () to 2.19 Ki

38 mm pressure, it changes to He () with abrupt changes in ma

Sp

xe5s

115p

1

physical properties such às density, dielectric constant andspecit

Sd

heat. He (II) is super fluid having so low energy that thermal motica of atoms do not take place, however, interatomic forces area so weak that it does not occupy solid state. Thus He (I) is liqut with properties of gas. It has following characteristics: a. It has very high thermal conductance i.e., 800 times of

5d

xe-11 1 1 L Sp

Xe-1 1

5d

copper. b. Ithas very low viscosity

111

1/100 or H, gas.

C. It has a very flat meniscus and very low surface tension ani

By unpairing of one period orbitals, two singly occupied orbitals comes into existence. Thus either two, four or six singly occupied orbitals can be formed instead of one, three

or five singly occupied orbitals. Hence XeF, XeF, or XeF are not formed.

creeps over the surface of glass container. d. Its electrical resistance is zero i.e., it is super conducmg

liquid. e. He (II) has much lower entropy.

5.6.4 VALENCE BOND APPROACH FOR XENON COMPOUNDS 1

2

:XeF

XeF

Xenondifuoride Ss Sp

Xenontetrafluoride

**

5d

5s

5p

Xe

ULL DIID CGin (in XeF.) Xet) dwith 3P

(inXeF)

SN 2 bp+3 lp -5

SN=4 bp +2 Ip =6

sp'd with 2 lp

H sp'd, G= Trigonal bipyramidal

H=sp'd, G =Octahedral

Shape = Linear

Shape = Square planar

3

:XcF% 5d UGin

Xenonhexafuoride 5s Sp Xe

CinXeF) SN

=

5d EIi

sp'd with I p

6 bp+ 1 lp=7

H sp'd', G= Pentagonal bipyramidal

Shape=

It should be

pentagonal pyramid. But

distorted OH. or monocapped OH.

F

L=0

H 0

F H0

p-Block Group 18 Elements: The Inert Family 5 5

XeO Venon

trioxIde

:Xe = O

(inX e O , -

Xenondioxydifluoride :Xe=0

Xenonoxytetrafluoride :Xe-F F

5s

5p

Xe

Cin Xe0,F,) sp with 1 lp =4

5s

Sd

Il1LLGin

sp'd with 1 lp

SN=4 bp +1 lp = 5, H=sp'd

bp+lp SN-3 H=sp, G= Tetrahedral Shape =

:XeOF

5d

Sp

5s

XeO,F

5d

5p

Xe

XeOF)

(inXeOF,) SN

sp'd with 1lp

5 bp + 1 lp = 6, H= sp'd*

G=T.b.p. See-saw shape saw horse G=Octahedral, Shape Square pyramid or distorted/irregular. Tetrahedral

Pyramidal

0 o*

one (pT-dr) multiple bond]

0

3 (pt-dr) multiple bond]

[2 (pT-dn) multiple bond]

XeO: Xenon trioxide

(in Xe0,)

5d

Sp

5s

Sp

SN=4 bp +0 lp =4, H =sp', G Tetrahedral, Shape Tetrahedral =

=0 4 (pT-dr) multiple bond]

Note: Electrons used inn-bond formation

are not

included in the

3.6.5 VALENCE SHELL ELECTRON PAIR REPULSION

S.No.

Formula

No. of

No. of bp

No. of

pairs 2

3

(Xenon

(Xenon tetrafluoride)

FOR XENON COMPOUNDS Structure

VSEPR explanation

(shape) Linear

5 electron pairs-trigonal bipyramid geometry with 3 Ip in equatorial

F

positions

difluoride)

XeF

(VSEPR) THEORY APPROACH

Ip

electron

XeF2

hybridised set of orbitals.

6

2

Square planar

6 electron pairs-octahedral

geometry, position

with 2

lp occupying axial

F

3.

Xe6 (Xenon hexafluoride)

XeO Xenon

8 7

7 electron pairs-pentagonal the axial position OR distorted octahedral

8+6-7 2

7 electron pairs -

bp involved in o bond formation, Ip involved in t bond formation and 1 Ip. Hence, it forms tetrahedral geometry Shape

XeO,F, (Xenon dioxy difluoride)

8+4+2

2

=7

Pyramidal

3 3

trioxide)

5.

Pentagonal pyramid

bipyramidal with 1 Ip occupying

6

pyramidal

4

bp involved in o bond formation, 2 bp involved in n bond formation, 1 Ip occupies equatorial position in

(46 +2T)

See-saw

pentagonal biypramidal geometry

F

XeO

0

(Xenon tetraoxide)

(4o+ 4t)

4 bp involved 4

bp

in involved in

Tetrahedral

bond formation

resulting in tetrahedral geometry

Note: Electrons involved inn bond formation must be subtracted before

primary shape of the molecule.

5.7 USES OF NOBLE GASES 5.7.1 USES OF HELIUM

o bond formation, t

counting

the number of electron

pairs

which determine the

gas in blood. This causes the painful condition called bends 'caisson sickness'. Helium is slightly soluble, so the risk of bends is not there or is reduced. or

(He)

1. Helium has the lowest boiling point (4.2 K) of any liquid and hence it is used (i) in cryoscopy to obtain the very low

temperatures required for superconductivity and lasers; (ii) as a cooling gas in one type of gas cooled nuclear reactor and (ii) as flow gas in gas-liquid chromatography.

2. Helium is used in weather balloons and airships. Despite the fact that hydrogen gas has low density, lighter, cheaper and is more readily available than He, it is helium which is used in weather balloons and not hydrogen gas. The reason being that hydrogen gas is highly inflammable as compared to helium. As helium is heavier than H2, lifting power of helium is 92.6% as compared to that of

H

high thermal conductivity, low viscosity and density, helium is used as flow gas in gas-liquid

3. Due to

chromatography.

4. It is used for filling electrical transformers. 5. Both helium and nitrogen gas are inert, but it is helium which is used in preference to nitrogen to dilute oxygen in the gas cylinders used by divers in deep sea diving (mixture of (He +0,) is used ratherthan (He + Na). This is due to the fact

that at high pressure, N, gas is highly soluble in blood as compared to He and when the diver comes out of the sea, a

sudden change in pressure (a region of high pressure to low pressure), causes degassing and releases bubbles of nitrogen

6. Helium is used to provide inert atmosphere for the meling of easily oxidisable metals such as magnesium, aluminum.

stainless steel etc.

7. It is used to produce and sustain powerful conduchng magnets, which are essential part of nuclear magnenc resonance (NMR) spectrometer and magnetic resonance

imaging (MRI) systems, used for chemical diagnosis 8. Mixture of He and O, is used to treat asthma as it is

ver

ight and hence difuses more rapidly than air throughpart choked lung passages. 9. Helium is

because

suitable for low temperature gas thermolu

a.

It has low

boiling point.

b.

It has

ideal gas behaviour.

5.7.2 UsES

near

OF

NEON

(Ne)

1. Neon emits a characteristie reddish orange

when

gloWw

ence

subjected to electric discharge at very low pressure.F and

a Small amount of neon is used in neon discharge tubes

fluorescent bulbs for advertising display purposes. Ower

2. As the light of neon signs have a better penetratinfo through fog and mist so these are used in beacon i safety of air navigation.

p-Block Group 18 Elements: The Inert Family 5.11 interatomic forces b. Noble gases being monoatomic have no therefore, they are Cxcept weak dispersion forces and Hence they have very liquefied at very low temperatures.

i d Ne is used as cryogenic refrigerant as it has over

imes 40 ti

the refrigerating capacity per unit volume than and three times that of liquid H,.

liquid

low boiling points.

gas lasers.

make tis Me hulbs are used in botanical garden and in green houses. used to

USES OF ARGON

5.7 1.

rovides inert

c. No, the products of hydrolysis are XeOF and XeO,F2 remain the where the oxidation states of all the elements

(Ar)

same as it was in the reacting state.

atmosphere for metallurgical processes. This

Used Mixture of Ar and Hg vapours is used in fluoroscent tubes. with N, gas is used in gas-filled electric lamps. . Argon along to N, gas for filling electric lamps because It is superior a.Thermal conductivity is Ar less than that of N, b. Ar is more inert than N, gas, thus it does not endanger the life of the tungsten filament and thereby enhances the life of the lamp. so no

heat is lost in

a.

are

those of xenon.

C. No chemical compound of He is known. Why?

Sol a. Since PtF, oxidises O, to 0,", Bartlett thought that PtF should also oxidise Xe to Xe

breaking the atoms.

enthalpies of

0, (1175 kJ mol')

because the ionisation and Xe (1170 kJ

mol)

are quite comparable. least ionisation b. Except Rn, which is radioactive, Xe has the

5.7.4 UsES OF KRYPTON (Kr) and valves.

2. Kr-85 is used in electronic tubes for

noble gas What prompted Bartlett to the discovery of

b. The mnajority of noble gas compounds Give reason.

protective (non-reactive) atmosphere for 5. It is used and Ge. growing crystals of Si

sign tubes

4HF

compounds?

as a

1. For filling luminous

+

ILLUSTRATION 5.4

c. Being monoatomic, it does not dissociate even at high

temperatures,

Xe0,F,

XeF +2H,0

of Ti (Kroll's process).

+2HF

+6)

(+6)

aluminium.

production

XeOF

XeF, +H,0

includes welding stainless steel, titanium, magnesium and in the

(+6)

(+6)

voltage regulation and

c.

in leak testers.

can be easily enthalpy among group 18 elements and hence or O. That is likes Oxidised by strong oxidising agents F, are that of xenon. noble of compounds gas why, majority Helium does not form chemical compounds because: i. Electronic configuration of He is 1s. The unpairing of

electron cannot be done in He and hence it

5.7.5 USES OF XENON (Xe)

cannot

form

chemical compounds.

1. Used in electric flash tubes for high speed photography.

ii.

lonisation enthalpy of He is very high.

2. Xe-133 is used as a radioisotope.

3. Perxenates are used in analytical chemistry as Oxidising

Consider the following compounds in their solid the value ofexpression. (a t b-c).

agents.

5.7.6 USES OF RADON (Rn) 1. Used in radioactive research. . Used in treatment of cancer and other malignant growths. 3.

Used for photographing 1.e.

locating defects

LLuSTRATION 5.5

materials the interiors of opaque and other metals and

in steel coatings

I. Cl,O

l1. 1,CI,

where

Total number of

known as noble Why are the elements of group 18 gases? Noble gases have very low boiling points. Why? Does the hydrolysis of XeF, lead to a redox reaction

compounds

have their valence shell present in group 18 with a few and therefore react

elements Orbitals completely filled

*he

iCments only as

Therefore, under certain conditions.

noble gases.

they are

in which central

atom

=

in cationic or anionic part.

Total number of compounds having 109°,28" bond angle

Sol.

I.ClO,

IEIO,° sp

II. 1,C,

known

ll. XeF,

either in cationic or anionic part.

LLUSTRATIDN 5.3

and find

of cationic or anionic part is sp° hybridised. b Total number of compounds having 90° bond angle either c

solids.

a=

state

ICIO,1 sp

(Ar> > He> Ne > Xe Kr> He>Ar> Ne (4)Ar > Kr> Xe (3) in Compounds formed when the noble gases get entrapped and inorganic certain organic the cavities of crystal lattices of (1) interstitial compounds

(2) clathrates

(3) hydrates

(4) picrates

reaction? 16. Which compound is prepared by the following

4) non-metals

Electron affinity for (1) that of halogens

a

noble

(3) that of oxygen family

gas is approximately equal to (2) zero (4) that of nitrogen family

5. The gaseous mixture used by deep seca divers for respiration

Xe + 2F2

Ni vessel 673 K, 5-6 atm

(1:5 volume ratio)

(1) XeF2

(2) XeF6

(3) XcF

(4) XeOF2

17. The two electrons in helium atom

1s

(2) He +0, mixture

(1)N, +0, mixture

(1) occupy different shells (2) have different spins

(4) neon +0, mixture

(3)Ar+O, mixture

6. The forces of cohesion in liquid helium are (1) covalent

(2) ionic

(3) van der Waals

(4) metallic

(3) have the same spins

(4)

(1) H

(2) He

(3) N

(4) Ar

(1) orange and red lines

(2) He, (4) He, Ne, Ar,

Kr and Xe.

. Inert gases such as helium behave like ideal gases over a

wIde range of temperature. However, they condense into the

SOlid state at very

subshell

(2) orange lines

is

Ne and Ar

(3) He, Ne, Ar and KR

same

(4) green lines (3) yellow lines 19. The noble gas which behaves abnormally in liquid state

&. The inert gas present in atmosphere are

(1) He and Ne

occupy different subshells of the

18. Helium gives a characteristic spectrum with

1. The lightest, non-inflammable gas is

low temperatures. It indicates that

at very

(1) Xe

(2) Ne

(3) He

(4) Ar

20. In order to prevent the hot metal filament from getting burnt, when the electric current is switched on, the bulb is filled with

low temperature there is a

(1) CH

(2) an inert gas

1) weak attractive force between the atoms

(3) CO

4) Cl

4 weak repulsive force between the atoms strong attractive force between the atoms 4) strong repulsive force between the atoms

10. The gas used for

11.

(1) Ne

compounds are known as

electronegative element 2) the most halides 3) the hydrogen

4.

(2) N2

in the order 14. The ease of liquefaction of noble gases decreases > He Kr> Xe (2) Xe > Kr >Ar> Ne He> Ne

with

(1) o x y g e n

(1)02

(4) He (3) Ar 13. In colour discharge tubes, which is used?

flating the tyres of aeroplanes is

(1) H,

(2) He

3)N

(4) Ar

element loactive X is

(0)u 232T 90

X decays to

21. Radon is a noble gas. Its radioactivity is used in the treatment of

(1) typhoid

(2) cancer

(3) cough and cold

(4) thyroid

22. Helium is used in gas balloons instead of hydrogen because (1) it is higher than H,

give

two inert gases.

(2) it is non-combustible (3) it is more abundant than H2

(2)26

27

(4) Ac 89

(4) its linkage can be detected easily 23. A helium atom on losing an electron becomes

(1) a-particle

5.14

Inorganic Chemistry

37. Which of the following cannot be formed

(2) hydrogen atom

(3) positively charged helium ion (4) negatively charged helium ion 24.

Liquid

flow fron

following liquids

lower level. Which of the climb up the wall of the glass vessel in

higher

a

can

to

a

(2) Liqiud He

(3) Liquid N,

(4) Water

(2) He

(3) He

(4) He

38. Which statement regarding He is incorreet? (1) It is used in gas cooled nuclear reactor.

which it is placed? (1) Alcohol

(1) He2

(2) It is used

as a

cryogenic agent

for

at low temperature.

(3) It is used to

25. Neon is extensively used in

carrying rrying out out eexperimen

produce and sustain powerful supercon

Superconducting

magncts.

(1) cold storage units (2) organic compounds

(4) It is used to fill gas balloons instead of H, beca because it is lighter and non-combustible.

(3) medicines

39. The idea that prompted Bartlett to prepare frst eve compound of noble gases was

(4) coloured electrie discharge lamps 26. The discovery of isotopes began with the experiments with

(1) Low bond dissociation enthalpy

(1) Xe

(2) Kr

(2) High bond energy of Xe-F

(3) Ar

(4) Ne

(3) Ionisation enthalpies

27. Which statement about noble gases is not correct? (1) Xe forms XeF,

of F-t in

of O2 and Xe

are

F, molecile

almost

same

(4) None of the above 40. Noble gases are also known as aerogens because

2)Ar is used in electric bulbs

(1) They occur in air

(3) Kr is obtained during radioactive disintegration

(2) They are rarely found in atmosphere

4) He has the lowest boiling point among all the noble gases

(3) They are most rarely found in atmosphere

28. In solid argon, the atoms are held together by

(4) None of the above

(1) ionic bonds

(2) hydrogen bonds

(3) van der Waals forces

(4) hydrophobic forces

41.

29. The van der Waals forces are the greatest in

Helium-oxygen mixture is used by deep sea divers preference to nitrogen-oxygen mixture because (1) Nitrogen is much less soluble in blood than helium

(1) neon

(2) argon

(2) Helium is much less soluble in blood than nitrogen

(3) krypton

(4) xenon

3) Nitrogen is highly soluble in water (4) Due to high pressure deep under the sea nitrogen

30. Electronegativity of an inert gas is

(1) high

(2) low

(3) negative

(4) zero

31. Which has the

same

Oxygen react to give poisonous nitric oxide. 42.

electronic

(1) Ag (3) Pb4

configuration as of inert gas? (2) Cu2

(4) Ti4

(4) Ar

(2) XeOF, and CaCN

(3) XeO, and CaCN,

(4) XeOF, and CaCO

(1) Orange and red lines

(2) Yellow lines

(3) Orange lines

(4) Green lines

(1) He

(2) Ar

compound? (1) Kr

(3) Ne

(4) Xe

(3) Ne

noble gas has

highest

and

least

respectively?

polarisability

(2) Ne, Kr

3) Kr, Ne

(4) Xe, He

35. Asthma patients use a mixture of . . . . . for respiration.

(1)0, and H,

(2) O, and He

(3) O, and Ar

(4) 0, and Ne

36. The solubility of noble gases in water shows the order:

(1) He> Ar> Kr> Ne> Ke (2) He> Ne>Ar> Kr> Xe (3) Xe> Kr>Ar> Ne > He (4) None of the above

following (2) Xe (4)Ar

noble gas does

not form

elal

45. Which of the following is not true about heliunm?

(1)

(1) He, Xe

CaCN, gives respectively:

(1) Xe0, and CaCO,

44. Which of the

33. Which noble gas is more soluble in water?

34. Which

and

43. Helium gives a characteristie spectrum with:

32. Which noble gas is not found in atmosphere? 1) Rn (2) Kr (3) Ne

Hydrolysis of XeF,

It

form clathrate compounds (2) It can diffuse through rubber and plastic materral can

(3) It has the highest first ionization energy (4) It has the lowest boiling point 46, Which

compound is prepared by the following re

Xe + F

Ni 673 K

(2: 1) volume ratio (1) XeF, (3) XeF

(2) XeF, (4) None of these

in

p-Block Group 18 Elements: The Inert Family clathrates (of xenon with water, the nature of bonding clathrates

In 1.

the

xenon and

water molecule is:

betv

)

ipole-induced dipolk interaction

Dipo.

2) Hydrogen bonding )

5.15

60. Which of the following is an explosive compound?

(1) XeO

(2) XeF2

(3) XeOF,

(4) XeOF

61. Incorrect statement regarding following reactions is:

+Excess H0,x +HF

Coordinate

(4)C o v a l e n t

nounds of

XeF%

Inert Gases

8Whichspecies (1) NeF,

is not

0

which does not

(2) Both are example of non-redox reaction

(3) 'Yis an oxyacid of xenon 4) X is explosive

exist is

(2) SF (4) XeF

(1) CF ) HeF 0. The

non-existent

62. XeFs dissolves in anhydrous HF to give a good conducting solution which contains:

(1) HXeFand F" ions (2) HF, and XeF ions

species is

(2) BrFs

(1) XeF ) SbF

(3) H and XeF, ion

(4) PF5

hybridisation of Xe in XeOF, molecule is () square planar, sp'd (2) square pyramidal, sp°d*

and . Geometry

(4) none of the above

3) tetrahedral, sp" 2. NeF exists as 0) solid

. . . .

4) none of these

prompted

Bartlett to prepare first

ever

(1) high bond energy of Xe-F and

xenon

were

almost similar

(1) sp'd', distorted octahedral

(2) sp'd, TBP

3) sp'd', pentagonal planar (4) No compound formed at all

(2) 0, and Xe have comparable ionization energies (3) Both O, and Xe are gases

4) none of the above 4. What are the products formed in the reaction of xenon

(4) 0, and Xe have comparable sizes 65. Consider the following properties of the noble gases.

hexafluoride with silicon dioxide?

(1) XeSio + HF

(2) XeF+ SiF

3)XeOF+SiF

(4) XeO + SiF

(1) They readily

form

compounds

which

are

colourless.

(11) They readily generally do not form ionic compounds. (II) Xenon has variable oxidation states in its compound.

$5 XeF, on complete hydrolysis gives

(1) XeO

(2) XeO

3) Xe0,

(4) Xe

(IV) The smaller He and Ne do not form clathrate compound

56. Xenon tetrafluoride has hybridisation and structure as

() sp tetrahedral

(2) sp'd square planar

) sp'a pyramidal

(4) sp'd octahedral

$7. In the clathrates of xenon with water, the nature of bonding Defween xenon and water molecule is

and

(ii) XeF,

(1)1, I1, II

(2) I1, 111, V

(3) 1, I1, IV

4) All

66. When a solution of XeO, is treated with metal fluoride, the product obtained is .

1) M Xe0,F]°

(2) M Xe0,F1

(3) M XeO,F]

(4) None of these

67. Xenon tetra-fluoride, XeF, is

(2) hydrogen bonding (4) dipole-induced dipole the molecules

Ving same number of lone pairs on Xe are (2) (i) and (ii) only (0)) and (i) only

3) (i)

(4) (i), (i) and (ii)

(1) XeO 3) XeOF

(2) XeF (4) Xe0,F2

and (ii) only 59. Which is planar molecule'?

The state of hybridisation of the central atomin 'A' and shape

(1) O, and Xe have comparable electronegativities

2) low bond energy of F-F in F

(1) covalent 3) coordinate ut of i) XeO, (ii) XeOF,

A' (M = Alkali metal cation)

64. The formation of O," [PFJ° is the basis for the formation of xenon fluorides. This is because:

compound of noble gas was

3) ionisation energies of O,

(4) None of these

63. MF+XeF^

of the species are:

atmospheric conditions. (2) liquid

under ordinary

3) gas 33. The idea which

"Y'+ HF

(1) XeF, can undergo partial hydrolysis

(2) XeF (4) KrF

(3) NeO The fluonide

+2H,0

known?

(1) See-saw shape and acts as a tluoride donor with AsF

(2) Square planar and acts as fluoride donor with NaF (3) Square planar and acts as a fluoride donor with PF (4) Tetrahedral and acts as a fluoride donor with SbF 68. Xe(g) + PtF,(g)

A-

25°C

60°

C

The products are:

() Xe°PF,I (11I) [XeF° PtF,J°

() XeF]° [PtF,1 (IV) [XeF,]" [Pt,F,1°

5.16

Inorganic Chemistry

(VI) [XeF]° [PF,T

(1) 1. VI, II

(2) 1, I1, III

(1) XeO,F,

(3) VI, II, ll

(4) 1. IV, V

(3) XeCl

69. Which

one

of the

following correctly represents Xe F

length?

70.

79. The compound that cannot be formed by Xe is:

(V) XeF 1° [PL,F,J°

(1) XeF,>XeF, > KeF,

(2) XeF, > XeF, > XeF

(3) XcF,> XeF, >XeF2

(4) None of these adduct. The

reacts with XeF, to form SbF cation and anion in the adduct are respectively: an

(1) Square pyramidal,

bond

Multiple Correct Answers Type Physical and Chemical Properties

shapes

of

1. The noble gases which do not form any (1) He (2) Ne

octahedral

2.

clathrate

(4) Kr

(3) Ar

(2) T-shaped, octahedral

Which of the following

noble gases do not

fluorine?

(3) Square planar, trigonal bipramidal 4) Square planar, octahedral 71. Consider the following transformations:

(1) Kr

(2) Xe

(3) He

(4) Ne

() XeF +NaF>Na [XeF,]° (1) 2PC1,() [PCI,1" [PCI,J° (IIT) [AI(H,0),1" +H,O [AIH,0),OH]** +H,o®

3. The noble gases found dissolved in some (1) He (2) Ne

Possible transformations are:

4.

react with

spring water are

(4) Ar

(3) Kr

Boiling point

and

melting point

of noble gases are in

(1) I. II, III

(2) I, III

order

3) I. II

(4) II, II

(1) He < Ne < Ar Ne> Kr> Ar> X

(3) He Ne>

72. Which of the following is an uncommon hydrolysis product (1) HF (3) Xe

(2) 0

that of molecular oxygen?

(4) XeO

(1) Ar

(2) Xe

(3) Kr

(4)Rn

73. Out of (G) XeO,, (i) Xe0,F, and (ii) XeO, the molecules having same number of lone pairs are (1) i) and (i) (3) i) and (ii)

[HXe04 +OH°

Ar> Xe

(2) (ii) and (ii)

6. The following observations are shown by 1. Itis used for filling

4) None of these

IX]+[Y] +0, +H,O

(1) HXeO, and Xe

(2) [Xc0

(3) Xe0 and Xe

(4) [XeO,1 and Xe

and XeO

75. XeF, and XeF, are separately hydrolyzed then:

(1) XeF, gives O, and XeF, does not (2) Neither of them gives HF (3) XeF, alone gives 0, (4) Both give out O, 76. Which of the following compounds has the same number of lone pairs as in I

(1) XeF2

(2) XeF

(3) XeO

(4) XeO

77. The noble gases can be separated by (1) Adsorption and desorption on activated hydrogen

airships and balloon for meteorological

purposes because of it power equal to 92% that ofH

2. With O,, it is used by deep sea divers for respiraion ami also used in the treatment of

The products [X] and [Y] in unbalanced reaction are:

respiratory

asthma. alloys that are easily oxidised. 4.

Used for inflating the tyre of big aeroplanes because t

lightness. Used in (1) Ne (3) He 5.

cryoscopic experiment. (2) Ar (4) Kr

7. He is added to the oxygen supply used by sea divers becau (1) it is less soluble in blood than N, a high pressure (2) it is lighter than N

(3) it

is

readily

miscible with O 4) it is less poisonous than N, 8. Which of the following statements are not correctr

(1) Ar is no used in electric bulbs.

(3) Electrolysis of their fuorides.

(2) Kr is obtained during radioactive decay

(4) Adsorption and desorption on charcoal

(3)Boiling point of helium

78. Which factor is responsible for the increase in boiling points

diseases lik

3. Providing inert atmosphere in the welding of metals tr

(2) Passing them through suitable solution

is the lowest among

noble u

gases.

(4) Xe forms XeOF

from He to Xe?

(1) Increase in polarisability (2) Decrease in polarisability (3) Decrease in I.E.

the

5. Which of the noble gases has its ionisation enthapy close

of XeF, and XeF?

74.

(2) XeF (4) XeO

(4) Mono-atomic nature

9. The coloured discharge tubes for advertisement main contains

18 Elements: The Inert Family

p-Block Group (4) Ar

(3) Dawar

3 )H e reacts

(2) Ramsay (4) Fischer-Ringe

(1) Bartlett and Lohman

Ne

21. Which one of the following does not exist?

with

Nenon

the most electropositive element

.

(

2)

(3)

the

most

halide the hydrogen

22. When

>

red

PtF

(2) enthalpy of vapourisation (4) solubility in water.

vapourization

which of the following tiuorides

are

statements are true? not

a

yellow

(2) [XeF°j [Pt,F,] (4) None

(3) Both (a) and (b) 23. Which of the incorrect?

a

(3) XeF, + PF, (4) 3XeF, +6H,0

that of xenon.

xenon

compounds

is

H[XcF,]

(2) XeF + RbF.

Hydrolysis of XeF, is redox reaction. lonisation enthalpy of molecular oxygen is very close to

reactions of

following

(1) XeF, + HF-

reactive.

mixed with Xe at room ionic solid. The product is

was

vapour

1) Xe®pFJ

He. This order represents

) ionisation enthalpy

) Nenon

deep

temperature to produce

4) Non-metals

of (1)ease

(2) XeF (4) XcF

(1) XcF, (3) ArF,

EN eleme

e >Kr> Ar> Ne

5.17

>[XeF5][RbF2] XeF3) [PF,I 2Xe + XeO, + 12HF + 02

4Only type of interactions between particles of noble gases are due to weak dispersion forces.

24. Which of the following statements are incorrect?

(1) XeOF can be stored in Ni containers for long period. (2) Xenon trioxide on treatment with xenonoxytetra-ffuoride (3) Partial hydrolysis of XeF, gives oxy-fluorides.

the correct order. 13. Select

) NeF,


XeF2- (melting point)

(4)

3) He < NeAr> Kr> Ne> Xe - (abundance in air)

14. Helium is used

as

flow gas in gas

liquid chromatography due

0

(1) high thermal conductivity (2) low density

(4) low thermal conductivity

(3) low viscosity Compounds of Inert Gases

pH>

XeF

glass reacts with XeF, to formn

(1) [XeF]

(2) XeO

(3) Xe0,F2

(4) XeOF

26. Which among the following statements is/are correct? (1) He has lowest boiling point in its group.

5. XeF, on reaction with H, gives

(2) He diffuses through rubber and polyvinyl chloride

(1) Xe

(2) HF

(3) He and Ne do not form clathrate.

(3) XeF

(4) XeF

(4) XeF and SbF, combine to form salt.

16. Which of the following compounds cannot be prepared by direct reaction between the constituent elements?

XeF

3) XeF

(2) XeO (4) Xe0,F2

17. Which amongst the following statements are corect?

(1) XeF, and SbF, combine to form salt.

(2) He and Ne do not form clathrates. 3) He has highest boiling point in its group. (4) He diffuses through rubber 8. Which of the possible following fluorides of Xenon is

Impossible?

(1) XeF2 9.

25.

10.5 xenon trioxide in solution forms hydrogen xenate ion. cannot be stored in glass vessel because silica (Si0,) in When

3) XeF6

(2) XeF

(4) XeF

27. Sclect the correct statement(s) regarding the fluorides of xenon.

(1) All three fluorides are volatile, readily subliming at room

temperature (298 K). (2) XeF and XeF, can act as fluoride ion acceptors as well as fluoride ion donors. (3) All three fluorides are powerful oxidizing agents. (4) All three fluorides are decomposed by water, XeF, slowly

and, XeF and XeF, rapidly. 28. Select the correct statements.

(1) XeO, reacts with KI in acidic medium to give I and I, (2) Xe0, disproportionate in basice medium (3) Perxenate [XeO,l disproportionate in basie medium. (4) XeF, reacts with glass

CnOn fiuorides are colourless and at room temperature are:

(1) Solid (3) Gases Di

(2) Liquid (4) Superfluid

of noble gas compounds were the basis of ( V), o n of an ionic solid, dioxygenyl hexafluoridoplat1nate was when O, reacts with PtF, This experiment

TPAF. carried out by

Linked Comprehension Type Paragraph 1

Noble gases have completely filled valence shell i.e.

ns'np", except He (Is ). Noble gases are monoatomic under normal conditions.

5.18

Inorganic Chemistry

Low boiling points of the lighter noble gases are due to weak van der Waals forces between the atoms and absence of any interatomic interactions. Xe reacts with F, to give a series of fluorides namely

ColumnI

3.

XeF, XeF, XeF, XeF, on complete hydrolysis gives Xe0

Column II

Ncon

a.

i.Cryogenic

b.

Helium

C

Xenon

ii.

d.

Argon

iv.

.

Radon

V.

Krypton

vi.

i.

lonisation energy

comparable to O,

1. Structure of XeF, is

(1) Linear

(2) Square planar

(3) Tetrahedral

(4) Pyramidal

2. Oxidation state of Xe in XeF, is

(1)+2

(2) +4

3) +6

4) +8

Advertising sign

Provides inert atmosphere i metallurgy Cancer treatment High speed

4. Match the following:

3. Argon is used in are welding due to its

() Flammability

Compound

(2) High calorifie value

a. XeF

(3) Low reactivity with metal

photography

Hybridisation Geometry and shape

i. sp

1. Linear

b.

XeF

i. sp'

2. Square planar

C.

XeF6

ii. sp'd

3. Expected pentagonal

(4) Lower the melting point of metal 4. XeF, and XeF, are expected to be

pyramid but distorted

(1) Reducing

(2) Oxidising

(3) Inert

4) Basic

octahedral d.

Matrix Match Type

5. Match the

Column I

ii.

C.

XeFs

i. sp

d.

XeO,

iv.

Xe0F XeO4

V.sp'd

f. 2.

.

|C. d.

XeF

e.

.

sp'd

1. Expected trigonal bu

ii. spd

2. Expected octahedron but square pyramid

c. Xe0,F,

sp'd

ii. sp'

3. Trigonal bipyramid with one position

XeO XeO

sp'd

d. XeOF,2

i.

Column I Square pyramidal Linear

iii.

Distorted octahedral

iv.

Square planar

V.

iv.sp'd

e. Ba,[Xe0,1vi. sp'dt

sp 6.

XeF2 XeOF XeF

b.

i.

Occupied

Column II a.

b. XeOF4

sp'

XeF

Hybridisation Geometry and shape T-shaped

(hybridisation of Xe)

b.

4. Expected tetrahedra but pyramidal

following:

a. XeOF,

Column II

(compound) XeF,

iv. sp'd

Compound

This section contains questions each with two columns-I and II. Match the items given in column I with that in column II.

a.

XeO

Pyramidal

iv. Tetrahedral

Column I

4. Trigonal bipyramid 5. Octahedron Column

.

XeF%

Basic gas evolves on heating

b.

(NH,),S

Oxidising agent

H,PO

C.

ii. | Disproportionation in basie

medium/heating

d.C e.

NO, A

iv.

Reacts with water/hydrolysis

p-Block Group

18 Elements: The Inert

Family 5.19

dhe items given in Column I with that in Column II and III

Match t h ei t e n

Column I Reactions

Partial hydrolysis of XeF

XeF, + H,o-

Column II

Column II

Products

Characteristics

XcF

P

sp'd', square pyramid

2HF

Partial hydrolysis of XeF XeF,+2H,0 Complete hydrolysis of XeF,

XeF+3H,0-

+

XeOF,

ii.

Xe0,F

6HF

Complete hydrolysis of XeF. 6XeF+12H,0

ii.

4HF

IV.

4Xe +24HF +30, +.

e.Xein excess) + F(g)

*

sp'd, linear

sp'd, folded square

r.

sp, pyramidal.

XeO

***

6.73K, 1 bar to Q. ForQ.8

the

11

questions given below by appropriately matching the information given in three Column

Column I

Column II

Noble gases

Characteristics ()

5s 5p

following table.

Column I l Characteristics (11)

Highest ease of liquefaction

3s3p

of the

Along with

O,, gas is used for deep sea diving

i.

High thermal conductivity, low Viscosity and density.

q.

Forms clathrate compounds

ii.

Its electronic configuration is:

r.Reactwith PtF

to

give orangered ionic

solid

[He]2s2p d.

22s 2p

iv.

Its name is derived from Greak

(3)d-iis

Numerical Value Type

(2) c - i i s

1. What is the oxidation number of Xe in XeOF,?

(4) d-ii-p

last 2. What is the total number of electrons present in the

9.For neon, CORRECT combination is: (2) a-ivT

3. What is the percentage of Argon in air? 4. What is the total number of unpaired electrons in inert gas?

(4) d - i S

For argon, CORRECT combination is: (2) a-iv-T (1)a-iv-4 (4) d - i S (3)-ii-s . For Xenon, CORRECT combination is

(0)b-i-4 3)b-i-4

orbit of

Argon?

(1) a-iv-

6)-i-s

for

advertising display purposes

word which means'inactive

&For helium, CORRECT combination is:

()c-i-p

It is used in discharge tubes and fiuorescent bulbs

S.

5. What is the total number of lone

pair of electrons present in

Xe in XeF,? 6. What is the oxidation sate of Xe in XeF;? 7. How many dn-pr bonds are there in Xe0,?

(2) b--14r (4) b-i1-9.T

Archives 2. Which of the reaction?

EE MAIN

following

reactions is

an

example

of redox

(1) XeF, + 0,F,- XeF, + O,

ngle Correct

Answer TyPpe C mineral clevite on heating gives ) He (2) Ke (3) Ar (4) Ra (AIEEE 2006)

(2) XeF, +PE

[XeF]* PF

(3) XeF +H,0 (4) XeF+ 2H,0

XeOF, +2HF Xe0,F, + 4HF (JEE Main 2017)

5.20

Inorganic Chemistry

3. The

products

reacts with cold obtained when chlorine gas

and dilute aqucous NaOH

are:

(1) CIO and CIO

(2) CIo, and ClO,

(3) Cl and ClO

(4) Cl and ClO, (JEE Main 2017)

exhibit rich stereochemistry and their geometries can L be considering the total number ofclect pairs in the val 1. Argon is uscd in arc welding because of its

dedu

valence shu

(1) low reactivity with metals. (2) ability to lower the melting point of metals. (3) flammability

JEE ADVANCED

(4) high

2. The structure of Xe0, is

Single Correct Answer Type 1. The

shape of NeO.F,

(2) planar 4) T-shaped

(1) linear

molecule is

(1) Trigonal bipyramidal

(2) Square planar

(3) Tetrahedral

(4) See-saw

(3) pyramidal

3. XeF and XeF, are expected to be

IT-JEE 2012) number of gases released 2. Under ambient conditions, the total reaction scheme shown below products in the final step of the

Complete

(2) reducing (4) strongly basic

(1) oxidising (3) unreactive

(IIT-JEE 200 Matrix Match Type

Hydrolysisp+ other produet

xef

calorific value

compounds listed in column I react with water. Match the result of the respective reactions with the appronra

1. All the

OH H.O

options listed in column slow disproportionation in OH /H,O Products

(1)0

(2) 1

(3)2

(4) 3 (JEE Advanced 2014)

(1) He

(2) Ne

(3) Kr

(4) Xe

Column I

ColumnI a.

(CH),SiC

b.

XeF

C.

Cl

d.

3. Which one has the highest boiling point?

II.

Hydrogen halide

P.

formation

Redox reaction

VCl

r.

Reacts with glass

.

Polymerisation 0, formation

(IIT-JEE 2010 (JEE Advanced 2015) Numerical Value Type

Linked Comprehension Type The noble gases have closed-shell electronic configuration and

are monatomic gases under normal conditions. The low boiling points of the lighter noble gases are due to the weak dispersion forces between the atoms and the absence of other interatomic

1. A list of species

having the formula XZ, is given below

XeF, SF. SiF, BF°. [Cu(NH),. [FeCI. [Co and [PtCI,1 Defining shape on the basis of the location of Xandl atomm the total number of species

interactions.

The direct reaction of xenon with fluorine leads to a series of compounds with oxidation numbers +2, +4 and +6, XeF, reacts violently with water to give Xe0. The compounds of xenon

having

a

square planar shau (JEE Advanced 204

2. The total number of lone pairs of electrons in N.O, 1s

(JEE Advanced 201

Answers Key EXERCISES

31.(4)

Single Correct Answer Type

36. (3)

37.(4)

41.(2)

42.(1) 47.(1) 52.(1) 57.(4)

5. (2)

8. (4)

4. (2) 9. (2)

46. (2)

10.(2)

51.(2)

13. (2)

14. (2)

15. (2)

18. (3) 23. (3)

20. (2)

21. (2)

17.(2) 22.(2)

19. (3) 24. (2)

25. (4)

26.(4)

27.(3)

28. (3)

29. (4)

30.(4)

1.(2) 6.(3) 11.(2)

16.(3)

2. (3)

. (2)

7.(4) 12. (3)

32.(1)

56. (2)

61.(3)

62. (2)

66. (2)

67.(3) 72.(4) 77.(4)

71.(1) 76. (1)

33. 38. 43. 48. 53. 58. 63. 68. 73. 78.

(4) (4) (2) (4) (3) (4) (3) (1) (1) (1)

34. (4) 39. (3) 44. (3) 49. (3)

54. (3) 59. (2) 64. (2)

69. (2) 74. (4) 79. (3)

35.(

40.(() 45.((1) 50.(()

55.((1) 60.((1) 65.(4 70.((2)

75.(3)

p-Block Group 18 Elements: The Inert Family

hole Correct

Answers

Type

Numerical Value Type

2. (3, 4)

14. (1, 2,3)

ARCHIVES

17. (1,2,4)

18. (4)

JEE Main

20. (1) 23. (1. 2) 26. (1, 2, 3, 4)

21. (3) 24. (2)

Single Correct Answer Type

5. (2)

8. (1,2)

4

11. (1, 2, 4)

7.(0) 0.(2)

13.(1, 3) 16.(2, 4) 19.(1)

22.(3)

5.(2. 3, 4)

1.(4) 6.((6)

1.(1)

27. (1,2,3,4)

28.(1.4)

JEE Advanced

inked Comprehension Type

Single 4. (2)

3. (3)

2.(1)

.2

2. (8)

2.(1)

Correct Answer

1.(4)

2.(3)

d

b

1.

1V

2

11

3.

111

V

i

iv,1 |ii,2 iv,1 iii,2

6.

i,iv

7.

i, p

8.(1)

3. (3)

Type 3. (4)

Linked Comprehension Type

Q.No. |

.

4. (0)

7.(4)

atrix Match Type

4.

3.(1)

3. (1, 4) 6. (3) 9. (2) 12. (3, 4) 15. (1,2)

1.1.2)

i

9.(3)

f

1V

iii V

iv

iii

vi

ii

1V

Vi

ii, 3

i,4

,

3

1, iv i, iii,

ii,r

e

iv

v, S 10. (1)

i,4 1i, ii,

iv

iv, s

11. (2)

V,5 ii, ii, iv 1,

1.(1)

2.(3)

3. (1)

Matrix Match Type

1. (a) p, s

(b)p, q

Numerical Value Type

1.(4)

2.(8)

(c) p, q,t

(d))P

5.(3)

5.21