Download The d-Block And f-Block Elements

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Cdf – 1
d & f-BLOCK ELEMENTS
Einstein Classes,
Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18
Ph. : 9312629035, 8527112111, E-mail [email protected],
www.einsteinclasses.com
Cdf – 2
CONCEPTS
C1
1.
1 10
Electronic configuration of the Transition Elements : It is (n  1)d
ns 1 2
Penultimat e Shell Valence Shell
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2.
d-Block elements are known as Transition elements.
f-Block elements are known as Inner Transition elements.
The three series
(i)
Sc to Zn
(ii)
Y to Cd
(iii)
La to Hg (excluding the elements Ce to Lu)
mainly constitute the three transition series. While Lanthanoids and Octinoids form the inner transition
elements.
Position of Transition Elements : They are between s- and p- Block elements.
The elements make up three complete rows corresponding to filling of 3d, 4d and 5d orbitals.
The fourth row which begins with the filling or 6d orbitals is still incomplete.
Half filled and completely filled orbitals are more stable. As there is small difference in energies of ns and
(n – 1)d orbitals, so several exception in electronic configuration exists.
e.g., Cr, Cu etc. Zn, Cd and Hg are the end members of the three transition series. There electronic
configuration in (n – 1)d10 ns2. The d-orbitals in these elements are completely filled in the ground state and
in there common oxidation states also.
Therefore they are often regarded as non-transition elements.
3.
Properties of Transition Elements :
C2
Physical Properties :
(i)
All transition elements display typical metallic properties such as high tensile strength, ductility,
malleability, high thermal and electrical conductivity and metallic lusture. Except Hg which is liquid at
room temperature.
(ii)
There melting and boiling point is high.
(iii) High melting point is  of strong interatomic bonding which involves the participation of both ns and
(n – 1)d electrons.
(iv) M.pt rises in any row upto d6 configuration except Mn and Tc and fall regularly as the atomic number
increases.
(v)
With exception Zn, Cd and Hg the transition elements are much harder and less volatile.
(vi) They have high enthalpy of atomisation.
(vii) Greater number of valence electrons, stronger the bond.
(viii) Enthalpy of atomisation of 4d and 5d is greater than first series elements.
(ix) The decrease in metallic radius coupled with increase in atomic mass results in increase in density of these
elements. From Ti to Cu density increases.
4.
Variation in Atomic and Ionic Radii :
Ions of the same charge in a given series show decrease in radius with increase in atomic number. This is
because the extra electron enters a d-orbitals each time the nuclear charge increases by unity. The shielding
effect of d-electrons is small. Thus the net attraction between the nuclear charge and the outermost
electrons increases and ionic radii decreases.
The atomic radii also decreases in the same way. The radii of the elements from Cr to Cu however are very
close to one another. This is due to successive addition of d-electrons from outer electrons i.e. (4s) from the
inward pull of the nucleus. As a result of this, the size of atom does not alter much in moving from Cr to Cu.
There is a gradual decrease in size of the 14 Lanthanide elements known as Lanthanide Contraction.
5.
Ionisation Enthalpies :
(i)
With increasing nuclear charge which accompanies the filling of inner d-orbitals there is an increase in first
ionisation enthalpy along each series of transition elements from left to right.
(ii)
But there is an exception for second and third ionisation enthalpy. e.g. for Cr and Cu the second ionisation
enthalpy is much higher than those of neighbours because of extra stability. These exceptions are because
of extra stability of half filled and completely filled d-orbitals.
Einstein Classes,
Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18
Ph. : 9312629035, 8527112111, E-mail [email protected],
www.einsteinclasses.com
Cdf – 3
6.
–
–
–
–
–
–
–
(i)
(ii)
(iii)
7.
8.
(i)
(ii)
(IE), of 5d elements are higher than 3d and 4d elements. This is due greater effective nuclear charge acting
on outer valence electrons because of poor sheilding of the nucleus by 4f electrons.
Oxidation State :
A characteristic property of the d-transition metals is their ability to exhibit several oxidation states.
The stability of O.S. depends on the nature of elements with which the transition metal is combined.
The highest O.S. of element is found in compounds of fluorides and oxides because of most
electronegative nature of F and O.
Except Sc, the most common O.S. of 3d series is +2 which arises from loss of two 4s electrons. This means
after Sc d-orbitals become more stable.
In the +2 and +3 O.S. the compounds are mostly ionic. In highest O.S. the compounds are mostly covalent,
formed by removal or sharing of d-electrons (as in MnO4–).
The element which given the greates number of O.S. occur in or near the middle of the series e.g. Mn exists
from +2 to +7.
Within a group, the maximum O.S. increases with atomic numbers.
Fe
+2, +3
OS
+2, +3, +4, +5, +6, +8
Transition elements also form compounds with O.S. (+1, 0)
When an element exits in more than one oxidation state, standard electrode potential stabilities of different
states w.r.t. oxidation. Cr2+ is unstable in H2O w.r.t. oxidation, Cr3+ is stable in H2O. Fe2+ is unstable in
aerated H2O and changes to Fe3+ w.r.t. to oxidation.
The electronic configuration of 2nd and 3rd rows do not always follow the pattern of the first row.
As in Nickel group, since a full shell of electrons is a stable arrangement, the place where this occurs is of
importance.
Ni
3d84s2
Pd
4d105s0
Pt
5d96s1
The d-levels complete in
Ni
Cu
3d104s1
Zn
3d104s2
Pd
4d105s0
Ag
4d105s1
Cd
4d10 5s2
Pt
Au
5d106s1
Hg
5d106s2
10
Although ground state has d configuration, Pd and the coinage metals Cu, Ag and Au behave typical
transition elements. This is because in their most common O.S. Cu(II) has a d9 configuration, and Pd(II)
and Au(III) have d8 configuration (incomplete d devel). However Zn(II), Cd(II) and Hg(II) have a d10
configuration. Because of these elements do not show the properties characteristic of transition elements.
Stability of O.S. of an element in compound is decided by following factors :
The energy of sublimation
The lattice energy
The solvation energy
Chemical reactivity :
The metals of the first series with the exception of Cu are relatively more reactive and are oxidised by
1 MH+
Magnetic Properties :
When magnetic field is applied to substances two types of magnetic behaviour is observed :
Diamagnetism : They are repelled by the applied field.
Paramagnetism :
–
They are attracted by the applied field
–
It is due to presence of unpaired e– or it is spin only.
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(iii)
–
Formula : µ 
n
no. of unpaired e 
(n  2)
Unit - Bohr magneton (MB)
Einstein Classes,
Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18
Ph. : 9312629035, 8527112111, E-mail [email protected],
www.einsteinclasses.com
Cdf – 4
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9.
–
µ  as n 
Formation of Coloured Ions :
Many Ionic and Covalent compounds of transition are coloured whereas compounds of s- and p- Block
elements are white. Colour may arise because of incomplete d- or f- shells. In a free isolated gaseous ions,
the five d-orbitals are degenerate. i.e., having indentical energy.
The surrounding gps which can be solvent molecules in solution or ligands in a complex or other ions in a
crystal lattice, affect the energy of some d-orbitals more than others. Now d-orbitals no longer degenerate
and thus they form two groups of orbitals of different energy. Thus in transition elements with a partly filled
d shell, it is possible to promote electrons from one d- level to another d* level of higher energy
(d- d* transition). There is a small difference in energy, and so light is absorbed in the visible region.
The colour of a transition metal complex is dependent on how big the energy difference is between the two
d- levels. Which depends on nature of the logand and the type of complex formed.
e.g.
[Ni(NH3)6]2+
blue
2+
[Ni(H2O)6]
green
2–
[Ni(NO2)6]
brown-red
–
–
10.
11.
(i)
(ii)
(i)
–
–
Two sets of d-orbitals with different energies in an octahedral complex.
ZnSO4 (Zn2+ with d10 configuration) are white as d-d* spectra are impossible and they are colourless.
In the series Sc(+3), Ti(+4), V(+5), Cr(+6), Mn(+7) all have empty d orbitals hence d-d* is impossible and
they should be colourless. But following ions in aqueous solution are :
VO22+
[O.S. +5]
pale yellow
2–
CrO4
[O.S. + 6]
deep yellow
MnO4–
[O.S. +7]
Intense purple
The colour arises by charge transfer e.g. in MnO4– an e– is momentarily transferred from O to the metal and
thus oxygen changes from O–2 to O–1 and manages from Mn(+7) to Mn(+6). Detail study is not in course.
Formation of complexed compounds :
This is due to following reasons, i.e., (i) comparatively smaller sizes of the metal ions (ii) The high ionic
charges (iii) Availability of d orbitals for bond formation.
Catalytic properties :
The catalytic activity of transition metals and their compounds is due to :
ability to adopt multiple oxidation states.
ability to form complexes.
Examples of transition metals and their compounds to act as catalyst
Fe(+3) catalyse the reaction between iodide and persulphate ions.
2I– + S2O82–  I2 + 2SO42–
2Fe3+ + 2I–  2Fe2+ + I2
2Fe2+ + S2O82–  2Fe3+ + 2SO42–
Catalyst at the solid surface involve the formation of bonds between reactant molecules and atoms of the
surface of catalyst.
First row transition elements utilise the 4d and 4s electrons for bonding. This has the effect of increasing
the concentration on the surface of catalyst and also weakening of the bonds in the reacting molecules.
Formation of Intensitial Compounds
Those compounds in which H, C and N are trapped inside the crystal lattices of the metal.
They are usually non-stoichiometric.
Einstein Classes,
Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18
Ph. : 9312629035, 8527112111, E-mail [email protected],
www.einsteinclasses.com
Cdf – 5
(i)
(ii)
(iii)
(iv)
–
–
–
C3
1.
They are neither typically ionic or covalent. e.g. TiC, Mn4N, Fe3F, TiH2 etc.
These formulae do not represent the normal oxidation state of the metal and thus non-stoichiometric
material is obtained with such composition as VH.56, TiH1.7
The main physical and chemical properties of these compounds are as follows :
Melting point is higher than normal metals.
They are very narol.
They retain metallic conductivity.
They are chemically inert.
Alloy Formation :
An Alloy is a blend of metals prepared by mixing the components.
Alloy may be homogeneous solid solution in which the atoms of one metals.
Inner Transition Elements (f-Block) :
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–
Lanthanides resembles more losely to each other as compare to transition elements.
They have only one stable oxidation state.
Actinoids shows wide range of oxidation states in elements. The study of actionoids is more complicated
 of their radioactive property also.
Lanthanoids : Properties
Electronic Configuration : (n – 2)f1-14(n – 1)d0-1ns2. Atoms of these elements have configuration with 6s2
common but with variable occupancy of 4f level.
However the electronic configuration of all the tripositive ions are same having the general form of 4fn
(n = 1 to 14) Pr (Praseodymium) [Xe]4f36s2
CeZ = 58
[Xe] 4f 5d 6s 2
Gd
[ Xe]
4f 7
Half filled orbital
more stable
Z = 59
5d 6s 2
inspite of [Xe]4f86s2
Atomic number Z = 64
Terbium (Tb) [Xe]4f96s2 (Z = 65)
Lutetium (Lu) [Xe]4f145d16s2 (Z = 71)
(Last element of 4f inner transition elements)
Atomic and Ionic Size :
The overall decrease in size (i.e., atomic and ionic) from Lanthanum to Leutetium (the Lanthanoid
Contraction). Thus contraction is of course similar to observe in an ordinary transition series. i.e. imperfect
shielding of one electron by another in the same sub-shell. However the shielding of one 4f electron by
another is less than one d-electron by another with the increase in nuclear charge along the series.
 of contraction of Lanthanoid series known as Lanthanoid contraction, causes the radii of the members of
the third transition series to be very similar to those of corresponding members of the second series.
The almost identical radii of Zr(160 pm) and Hf (159 pm), a consequence of the Lanthanoid contraction.
Oxidation States : +3 is the predominant O.S. occasionally they do exist in +2, +4 O.S. e.g. Ce+4 formation
is favoured by its noble gas configuration, but it is strong oxidant reverting the common +3 state.
Einstein Classes,
Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18
Ph. : 9312629035, 8527112111, E-mail [email protected],
www.einsteinclasses.com
Cdf – 6
E X E R C I S E (OBJECTIVE)
2.
3.
4.
5.
6.
Out of SiCl4, TiCl4, PO43—, SO42—, CrO42—, CCl4
isostructural are
(a)
SiCl4, TiCl4
(b)
SO42—, CrO42—
(c)
both
(d)
none
7.
Os
(b)
Mn
(c)
Cr
(d)
Co
(A) NH4VO3 is heated.
(B) (NH4)2Cr2O7 is heated :
Maximum oxidation state is shown by
(a)
When
8.
Following elements do not show the properties
characteristics of d-block elements
(a)
in both cases N2 is formed
(b)
in both cases NH3 is formed
(c)
in (A) NH3 and in (B) N2 are formed
(d)
in (A) N2 and in (B) NH3 are formed
FeCr2O4 (chromite) is converted to Cr following
steps :
(a)
Cu, Ag, Au
(b)
Zn, Hg, Cd
I
II
III
Chromite 

Na 2 CrO 4 

Cr2 O 3 
Cr
(c)
Sc, Ti, V
(d)
Fe, Co, Ni
I, II and III are
AgCl and NaCl are colourless NaBr and NaI are
also colourless but AgBr and AgI are coloured. This
is due to
I
II
III
(a)
Na2CO3/air, 
C
C
(b)
NaOH/air, 
C, 
Al, 
(c)
NaOH/air, 
C, 
Mg, 
(d)
conc. H2SO4,  NH4Cl, 
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1.
(a)
Ag+ polarises Br— and I—
(b)
Ag+ has unpaired d-orbital
(c)
Ag+ depolarised Br— and I—
(d)
none is correct
9.
Which is not true statements ?
C, 
When H2O2 is added to an acidified solution of
K2Cr2O7
(a)
(a)
ions of d-block elements are coloured due
to d—d transition
solution turns green due to formation of
Cr2O3
(b)
(b)
ions of f-block elements are coloured due
to f—f transition
solution turns yellow due to formation of
K2CrO4
(c)
(c)
[Sc(H2O)6]3+, [Ti(H2O)6]4+ are coloured
complexes
a deep blue-violet coloured compound
CrO(O2)2 is formed
(d)
solution gives green ppt of Cr(OH)3
(d)
Cu+ is colourless ion.
10.
Match the catalyst in column X with their uses in
column Y
Column X
A:
TiCl4
I:
Column Y
Adams catalyst
in reduction
Match the compounds of column X with oxidation
state of column Y
Column X
Column Y
I
[Cr(H2O)6Cl3]
5
II
CrO5
4
III
K3CrO8
6
(NH3)3CrO4
3
B:
PdCl2
II :
in preparation
of (CH3)2SiCl2
IV
C:
Pt/
III :
Reppe
synthesis
D:
E:
(a)
(b)
(c)
(d)
Cu
IV :
Ni
A
IV
IV
V
II
V:
B
V
V
IV
I
Einstein Classes,
C
I
II
I
III
used as the
catalyst in
polythene
production
Wake process
for converging
C2H4 to
CH3CHO
D
E
II
III
I
II
III
II
V
IV
11.
I
II
III
IV
(a)
3
6
5
4
(b)
3
4
5
6
(c)
4
5
6
3
(d)
6
5
4
3
For CrO3 following is not true statement
(a)
it is called chromic acid
(b)
it is colourless due to 3d0 configuration
(c)
it is bright orange solid and colour arises
due to charge transfer
(d)
it is toxic and corrosive
Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18
Ph. : 9312629035, 8527112111, E-mail [email protected],
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Cdf – 7
pH  x
(c)
13.
14.

(b)

KCl + K2Cr2O7 + conc. H2SO4 
20.


(c)

MnO2 + conc. HCl 
(d)

KCl + F2 

21.
Which is not true statement about KMnO4
(d)
FeSO4 solution gives brown colour ring in testing
nitrates or nitrites. This is
(a)
[Fe(H2O)5NO]2+
(b)
[Fe(H2O)5NO2]2+
(c)
[Fe(H2O)4(NO)2]2+
(d)
[Fe(H2O)4NO]2+
Ni2+, in traces, can be tested using
(a)
sodium nitroprusside
(b)
dimethyl glyoxime
(c)
ammonium sulphocyanide
(d)
potassium ferocyanide
CuSO4 can be estimated volumetrically
(a)
its solution in unstable in acidic medium
by reaction with KI following by reaction
with Na2S2O3
its small quantity added to conc. H2SO4,
a green coloured solution containing
MnO3+ ions is formed
MnO4— changes to Mn2+ in basic solution
it is self-indicator in Fe2+ or C2O42—
titration
22.
(b)
by reaction with BaCl2
(c)
by reaction with K4Fe(CN)6
(d)
none is correct
Which is correct statement ?
(a)
Pyrolusite is MnO2 used to prepare KMnO4. Steps
are
ammoniacal CuCl is used to measure the
amount of CO in gas samples
(b)
ammoniacal CuCl gives red ppt. with
CH  CH
I
II
MnO 2 

MnO 24 

MnO 4
(c)
both correct
I and II are
(d)
none is correct
(a)
(b)
(c)
(d)
fuse with KOH/air, electrolytic oxidation
23.
When KCN is added to CuSO4 solution
fuse with KOH/air, electrolytic reduction
(a)
KCN acts a reducing agent
fuse with conc. HNO3/air, electrolytic
reduction
(b)
KCN acts as complexing agent
(c)
K3[Cu(CN)4] is formed
all correct
(d)
all correct
Fe is made passive by
dil. H2SO4
(b)
dil HCl
Out of AgNO3, AgF and AgClO4, water soluble salts
are
aqua regia
(d)
conc. H2SO4
(a)
AgF
Which is not ture statement about FeO ?
(b)
AgF, AgNO3
(a)
(c)
AgF, AgNO3, AgClO4
(d)
none
(a)
(c)
(b)
(c)
(d)
18.
19.
8 and 9

KMnO4 + con. HCl 
(c)
17.
(d)
(a)
(b)
16.
8 and 4
pH
Cl2 gas is obtained by various reactions but not by
(a)
15.
pH  y
Cr2 O 72  CrO 42   Cr2 O 72
values x and y can be
(a)
4 and 5
(b)
4 and 8
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12.
24.
it is non-stoichiometric and is metal
deficient
it is basic oxide
25.
its aqueous solution changes to Fe(OH)3
and then to Fe2O3.(H2O)n by
atmospheric oxygen
it gives red colour with KCNS
In Na2[Fe(CN)5NO], sodium nitrophrusside :
26.
Stability of Cu+ and Ag+ halide complexes is in order
(a)
I > Br > Cl > F (b)
F > Cl > Br > I
(c)
Cl > F > I > Br (d)
Br > I > Cl > F
Which of them exists as white salt is in anhydrous
state ?
(a)
oxidation state of Fe is +1
(a)
CuF2
(b)
CuSO4
(b)
this has NO+ as ligand
(c)
both
(d)
none
(c)
both correct
(d)
none is correct
Einstein Classes,
Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18
Ph. : 9312629035, 8527112111, E-mail [email protected],
www.einsteinclasses.com
Cdf – 8
27.
When KI (excess) is added to
A.
Gun metal
1.
Lead + Tin
I:
CuSO4
B.
German silver
2.
II :
HgCl2
Copper + Tin +
Zinc
III :
Pb(NO3)2
C.
Brass
3.
Copper + Zinc
(a)
a white ppt of CuI in I, a orange ppt HgI2
in II and a yellow ppt PbI2 in III
D.
Solder
4.
Copper + Zinc
+ Nickel
(b)
a white ppt of CuI in I, an orange ppt
dissolving to HgI42— in II, and a yellow
ppt of PbI2 in III
Codes :
a white ppt of CuI, HgI2 and PbI2 in each
case
(c)
(d)
29.
30.
31.
Magnetic moment of Cr(Z = 24), Mn+ (Z = 25) and
Fe2+ (Z = 26) are x, y, z. They are in order :
B
C
D
(a)
1
3
2
4
(b)
4
2
1
3
(c)
2
4
3
1
(d)
3
1
2
(a)
x<y<z
(b)
x=y<z
An acidic solution contains Cu , Pb2+ and Zn2+. If
hydrogen sulphide gas is passed through this
solution, the preipitate will contain
(c)
z<x=y
(d)
x=y=z
(a)
CuS and ZnS
34.
Interstitial compound is formed by
(b)
PbS and ZnS
(a)
Fe, Co
(b)
Co, Ni
(c)
CuS and PbS
(c)
Fe, Ni
(d)
all
(d)
CuS, PbS and ZnS
A jeweller is selling 22-carat gold articles with 95%
purity, it is approximately
(a)
exact
(b)
3.5% higher
(c)
3.5% lower
(d)
5% lower
35.
Paramagnetism is given by the relation
2+
Ti is purple while Ti4+ is colourless, because :
(a)
there is no crystal field effect in Ti4+
(b)
Ti2+ has 3d2 configuration
(c)
Ti4+ has 3d2 configuration
(d)
Ti4+ is a very small cation when compared
to Ti2+ and hence does not absorb any
radiation
µ  2 s(s  1) magnetons where ‘s’ is the total
spin. On this basis, the paramagnetism of Cu+ ion
is :
32.
(a)
3.88 magnetones
(b)
2.83 magnetones
(c)
1.41 magnetones
(d)
zero
36.
The oxygen-carrying pigment, oxyhaemocyanin,
containing two copper ions is diamagnetic, because
(a)
the two copper ions are in +1 oxidation
state
(b)
one of the copper ions is in +1 oxidation
state and the other is in +2 oxidation
state
(c)
(d)
33.
4
2+
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28.
none is correct
A
there are ferromagnetic interactions
between the two copper ions
List I
List II
(Alloys)
(Constituents)
Einstein Classes,
List I
List II
(Metals)
(Ores)
A.
Zinc
1.
Azurite
B.
Tin
2.
Carnallite
C.
Copper
3.
Calamine
D.
Magnesium
4.
Cassiterite
A
B
C
D
(a)
3
4
2
1
(b)
3
4
1
2
(c)
4
1
3
2
(d)
4
3
2
1
Codes :
there are strong anti-ferromagnetic inter
actions between the two copper ions
Match List I with List II and select the correct answer using the codes given below the lists :
Match List I with List II and select the correct
answer using the codes given below the lists
37.
Haemoglobin and Chlorophyll contain
(a)
Fe, Co
(b)
Fe, Mn
(c)
Mg, Fe
(d)
Fe, Mg
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Cdf – 9
39.
In Cr2O72— every Cr is linked to
ANSWERS
(a)
two O atoms
(b)
three O atoms
(c)
four O atoms
(d)
five O atoms
For Ni and Pt different I.P. values are given
below :
1.
c
14.
c
27.
b
2.
a
15.
a
28.
c
3.
b
16.
c
29.
d
(IP)1  (IP) 2
(IP) 3  ( IP) 4
4.
a
17.
d
30.
b
Ni
2.49
8.80
5.
c
18.
c
31.
d
Pt
2.60
6.70
6.
a
19.
a
32.
a
7.
c
20.
b
33.
c
8.
b
21.
a
34.
c
hence :
(a)
(b)
(c)
(d)
nickel (II) compounds tend to be thermo
dynamically more stable than platinum
(II)
w E
w IN
w S
.e T
in E
st IN
ei C
nc L
la AS
ss S
es ES
.c
om
38.
platinum (IV) compounds tend to be
more stable than nickel (IV)
both correct
none is correct
Einstein Classes,
9.
c
22.
c
35.
b
10.
a
23.
d
36.
b
11.
b
24.
c
37.
d
12.
c
25.
a
38.
c
13.
b
26.
c
39.
c
Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18
Ph. : 9312629035, 8527112111, E-mail [email protected],
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Cdf – 10
TEST YOURSELF
2.
3.
4.
5.
6.
7.
8.
9.
10.
Only +2, +3, +4 oxidation states are shown by
(a)
Sc, Ti
(b)
Fe, Ni
(c)
Ti, Ni
(d)
Zn, Ni
The ability of d-block elements to form complexes is
due to
(a)
small and highly charged ion
(b)
vacant low energy orbitals to accept lone
pair of electrons from ligands
(c)
both correct
(d)
none is correct
Which is correct statement ?
w E
w IN
w S
.e T
in E
st IN
ei C
nc L
la AS
ss S
es ES
.c
om
1.
(a)
in less acidic solution K2Cr2O7 and H2O2
gives violet coloured diamagnetic
CrO(O2)(OH)]— ion.
(b)
in alkaline H2O2, K3CrO8 (with
tetraperoxo species [Cr(O2)4]3— is formed
(c)
in ammonical solution (NH3)3CrO4 is
formed
(d)
all correct
In alkaline solution MnO4— changes to
(a)
MnO42—
(b)
MnO2
(c)
Mn2O3
(d)
MnO
Which oxides will not give metal on heating ?
(a)
HgO
(b)
ZnO
(c)
Ag2O
(d)
all
Most common oxidation state of lanthanides is
(a)
+2
(b)
+3
(c)
+4
(d)
+5
The purest form of Fe is
(a)
stainless steel
(b)
steel
(c)
cast iron
(d)
wrought iron
Maximum magnetic moment is shown by
(a)
d5
(b)
d6
(c)
d7
(d)
d8
Silver ornaments turns black by atomospheric
(a)
O2
(b)
N2
(c)
Cl2
(d)
H 2S
ANSWERS
Due to lanthanide contraction
(a)
Fe, Co, Ni have equal size
(b)
Zr and Hf have equal size
(c)
all f-block ions have equal size
(d)
all isoelectronic ions have equal size
Einstein Classes,
1.
c
6.
b
2.
c
7.
d
3.
d
8.
a
4.
b
9.
d
5.
b
10.
b
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Ph. : 9312629035, 8527112111, E-mail [email protected],
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