Chemistry - d and f block Elements
Exam Duration: 45 Mins Total Questions : 30
Electonic configuration of a transition element X in +3 oxidation state is [Ar]3d5. What is its atomic number?
- (a)
25
- (b)
26
- (c)
27
- (d)
24
Among the following, the compound that does not exist is
- (a)
K2TiO4
- (b)
K2TiF6
- (c)
TiO2
- (d)
TiCl4
The number of unpaired electrons present in Ni2+ is
- (a)
8
- (b)
4
- (c)
2
- (d)
0
Which of the following does not show any colour in solution?
- (a)
V3+
- (b)
Co2+
- (c)
Cr3+
- (d)
Sc3+
Which of the following does not belong to 3d-transition series?
- (a)
Fe
- (b)
Cu
- (c)
Au
- (d)
Co
Which of the following pair of compounds shows similar colour in aqueous medium?
- (a)
FeCl2 and MnCl2
- (b)
COCl2 and CuCl2
- (c)
VOCl2 and feCl2
- (d)
FeCl3 and CuCl2
Among the following elements, the element with lowest enthalpy of atomisations
- (a)
Sc
- (b)
Cr
- (c)
Cu
- (d)
Zn
Gadolinium belongs to 4f-series. It's atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?
- (a)
[Xe]4f7, 5d16s2
- (b)
[Xe]4f6, 5d26s2
- (c)
[Xe]4f8, 6d2
- (d)
[Xe]4f9, 5d1
Metallic radii of some transition elements are given below. Which of these element will have highest density?
Element | Fe | Co | Ni | Cu |
---|---|---|---|---|
Metallic radii/pm | 126 | 125 | 125 | 128 |
- (a)
Fe
- (b)
Ni
- (c)
Co
- (d)
Cu
The basicity of lanthanoid hydroxides, across the lanthanoid series
- (a)
decreases
- (b)
increases
- (c)
first decreases and then increases
- (d)
first increases and then decreases
Actinoids possess
- (a)
variable valency
- (b)
12 elements
- (c)
all synthetic elements
- (d)
only short-lived isotopes
When SO2 is passed through an acidified K2Cr2O7 solution, the oxidation state of sulphur changes from
- (a)
+4 to 0
- (b)
+4 to +2
- (c)
+4 to +6
- (d)
+6 to +4
A transition metal ion possess a magnetic moment of \(\sqrt{15}\)BM, the number of unpaired electrons present in this metal ion is
- (a)
1
- (b)
2
- (c)
3
- (d)
4
The colour o the compound containing Ti3+ ion is purple. It absorbs the wavelength of complement colour of
- (a)
blue
- (b)
green
- (c)
red
- (d)
greenish yellow
For the ions, Cu2+(3d9) and Cu+(3d10), the correct statement is
- (a)
Cu2+ is more stable than cu+
- (b)
Cu2+ is less stable than Cu+
- (c)
Cu2+ and Cu+ ions are equally stable
- (d)
Stability of Cu+ and Cu2+ depends on the nature of copper salts
The purple colour of KMnO4 is due to
- (a)
resonance in MnO4- ion
- (b)
charge transfer
- (c)
ionic nature of KMnO4
- (d)
partially filled d-orbitals
KMnO4 acts as oxidising agent in acidic medium. The number o moles of KmnO4 that will be needed to react with one mole of sulphide ions in acidic solution is
- (a)
\(2\over 5\)
- (b)
\(3\over 5\)
- (c)
\(4\over 5\)
- (d)
\(1\over 5\)
The addition of acidified K2Cr2O7 solution to Sn2+ salts, causes a change of Sn2+ to
- (a)
Sn+
- (b)
Sn3+
- (c)
Sn4+
- (d)
Sn
Which of the following arrangements does not represent the correct order of the property stated against it?
- (a)
V2+ < Cr2+
2+ < Fe2+ paramagnetic behaviour - (b)
Ni2+ < Co2+ < Fe2+ < Mn2+ ionic size
- (c)
Co3+
3+ 3+ 3+ stability in aqueous solution - (d)
Sc< Ti
Four successive members of the first row transition elements listed below with atomic numbers. Which of them is expected to have the highest EoM3+/M2+ value?
- (a)
Cr(Z=24)
- (b)
Mn(Z=25)
- (c)
Fe(Z=26)
- (d)
Co(Z=27)
Iron exhibits +2 and +3 oxidation states. Which of the following statements about iron is incorrect?
- (a)
Ferrous oxide is more basic in nature than the ferric oxide
- (b)
Ferrous compounds are relatively more ionic than the corresponding ferric compounds
- (c)
Ferrous compounds are less volatile than the corresponding ferric compounds
- (d)
Ferrous compounds are more easily hydrolysed than the corresponding ferric compounds
The outer electron configuration of Gd (Atomic number 64) is
- (a)
4f35d56s2
- (b)
4f8 5d0 6s2
- (c)
4f4 5f4 6s2
- (d)
4f7 5d1 6s2
In context of the lanthanoids, which of the following statements is not correct?
- (a)
There is a gradual decrease in the radii of the members with increasing atomic number in the series.
- (b)
All the members exhibit +3 oxidation state.
- (c)
Because of similar properties the separation of lanthanoids is not easy
- (d)
Availability of 4f electrons results in the formation of compounds in +4 state for all the members of the series.
The correct order of \(E^o_{M^{2+}/M}\) values with negative sign for the four successive elements Cr, Mn, Fe and Co is
- (a)
Mn > Cr > Fe > Co
- (b)
Cr > Fe > Mn > Co
- (c)
Fe > Mn > Cr > Co
- (d)
Cr > Mn > Fe > Co
Large number of oxidation states are exhibited by the antinoids than those by the lanthanoids, the main reason being
- (a)
4f orbitals more diffused than the 5f orbitals
- (b)
lesser energy difference between 5f and 6d than between 4f and 5d-orbitals.
- (c)
more energy difference between 5f and 6d orbitals than between 4f and 5d orbitals
- (d)
more reactive nature of the actinoids than the lanthanoids
Lanthanoid contraction is caused due to
- (a)
the appreciable shielding on outer electrons by 4f electrons from the nuclear charge.
- (b)
the appreciable shielding on outer electrons by 5d electrons from the nuclear charge
- (c)
the same effective nuclear charge from Ce to Lu
- (d)
the imperfect shielding on outer electrons by 4f electrons from the nuclear charge
Calomel (Hg2Cl2) on reaction with NH4OH gives
- (a)
HgO
- (b)
Hg2O
- (c)
NH2 - Hg - Hg - Cl
- (d)
HgNH2Cl
Of the following outer electronic configurations of atoms, the highest oxidation state is achieved by which one of them?
- (a)
(n-1)d8ns2
- (b)
(n-1)d5ns1
- (c)
(n-1)d3ns2
- (d)
(n-1)d5ns2
What would happen, when solution of potassium chromate is treated with an excess of dilute nitric acid?
- (a)
Cr3+ and Cr2O72- are formed
- (b)
Cr2O72- and H2O are formed
- (c)
Cr2O42- is reduced to +3 state of Cr
- (d)
None of the above