d- and f-Block Elements

Magnetic moment 2.84 B.M. is given by (At. nos. Ni = 28, Ti = 22, Cr = 24, Co = 27)

1. Cr2+
2. Co2+
3. Ni2+
4. Ti3+

Because of lanthanoid contraction, which of the following pairs of elements have nearly same atomic radii? (Numbers in the parenthesis are atomic numbers)

1. Zr(40) and Hf(72)
2. Zr(40) and Ta(73)
3. Ti(22) and Zr(40)
4. Zr(40) and Nb(41)

The reaction of aqueous KMnO4 with H2O2 in acidic conditions gives

1. Mn4+ and O2
2. Mn2+ and O2
3. Mn2+ and O3
4. Mn4+ and MnO2

Magnetic moment 2.83 BM is given by which of the following ions? (At. nos. Ti = 22, Cr = 24, Mn = 25, Ni = 28)

1. Ti3+
2. Ni2+
3. Cr3+
4. Mn2+

Reason of lanthanoid contraction is

1. negligible screening effect of 'f'-orbitals
2. increasing nuclear charge
3. decreasing nuclear charge
4. decreasing screening effect.

KMnO4 can be prepared from K2MnO4 as per the reaction, 3MnO42- + 2H2O 2MnO4- + MnO2 + 4OH- The reaction can go to completion by removing OH- ions by adding

1. CO2
2. SO2
3. HCl
4. KOH

Which of the following does not give oxygen on heating?

1. K2Cr2O7
2. (NH4)2Cr2O7
3. KClO3
4. Zn(ClO3)2

Which of the following statements about the interstitial compounds is incorrect?

1. They are much harder than the pure metal.
2. They have higher melting points than the pure metal.
3. They retain metallic conductivity.
4. They are chemically reactive.

Which of the following lanthanoid ions is diamagnetic? (At. nos. Ce = 58, Sm = 62, Eu = 63, Yb = 70)

1. Eu2+
2. Yb2+
3. Ce2+
4. Sm2+

The outer electronic configuration of Gd (At. No. 64) is

1. 4f5 5d4 6s1
2. 4f7 5d1 6s2
3. 4f3 5d5 6s2
4. 4f4 5d5 6s1

Sc (Z = 21) is a transition element but Zn (Z = 30) is not because

1. both Sc3+ and Zn2+ ions are colourless and form white compounds.
2. in case of Sc, 3d orbitals are partially filled but in Zn these are filled.
3. last electron is assumed to be added to 4s level in case of Zn.
4. both Sc and Zn do not exhibit variable oxidation states.

The catalytic activity of transition metals and their compounds is ascribed mainly to

1. their magnetic behaviour
2. their unfilled d-orbitals
3. their ability to adopt variable oxidation states
4. their chemical reactivity

Which of the following exhibits only + 3 oxidation state?

1. U
2. Th
3. Ac
4. Pa

Which one of the following does not correctly represent the correct order of the property indicated against it?

1. Ti < V < Cr < Mn : increasing number of oxidation states
2. Ti3+ < V3+ < Cr3+ < Mn3+ : increasing magnetic moment
3. Ti < V < Cr < Mn : increasing melting points
4. Ti < V < Mn < Cr : increasing 2nd ionization enthalpy

Four successive members of the first series of the transition metals are listed below. For which one of them the standard potential ( E M2+/M ) value has a positive sign?

1. Co (Z = 27)
2. Ni (Z = 28)
3. Cu (Z = 29)
4. Fe (Z = 26)

Identify the alloy containing a non-metal as a constituent in it.

1. Invar
2. Steel
3. Bell metal
4. Bronze

Which of the statements is not true?

1. On passing H2S through acidified K2Cr2O7 solution, a milky colour is observed.
2. Na2Cr2O7 is preferred over K2Cr2O7 in volumetric analysis.
3. K2Cr2O7 solution in acidic medium is orange.
4. K2Cr2O7 solution becomes yellow on increasing the pH beyond 7.

For the four successive transition elements (Cr, Mn, Fe and Co), the stability of +2 oxidation state will be there in which of the following order? (At. nos. Cr = 24, Mn = 25, Fe = 26, Co = 27)

1. Mn > Fe > Cr > Co
2. Fe > Mn > Co > Cr
3. Co > Mn > Fe > Cr
4. Cr > Mn > Co > Fe

Acidified K2Cr2O7 solution turns green when Na2SO3 is added to it. This is due to the formation of

1. Cr2(SO4)3
2. CrO42-
3. Cr2(SO3)3
4. CrSO4

Which of the following oxidation states is the most common among the lanthanoids?

1. 4
2. 2
3. 5
4. 3

Which of the following ions will exhibit colour in aqueous solutions?

1. La3+ (Z = 57)
2. Ti3+ (Z = 22)
3. Lu3+ (Z = 71)
4. Sc3+ (Z = 21)

Which of the following ions has electronic configuration [Ar]3d6? (At. nos. Mn = 25, Fe = 26, Co = 27, Ni = 28)

1. Ni3+
2. Mn3+
3. Fe3+
4. Co3+

Which of the following pairs has the same size?

1. Fe2+, Ni2+
2. Zr4+, Ti4+
3. Zr4+, Hf4+
4. Zn2+, Hf4+

Which one of the elements with the following outer orbital configurations may exhibit the largest number of oxidation states?

1. 3d54s1
2. 3d54s2
3. 3d24s2
4. 3d34s2

Out of TiF62-, CoF63-, Cu2Cl2 and NiCl42- (Z of Ti = 22, Co = 27, Cu = 29, Ni = 28) the colourless species are

1. Cu2Cl2 and NiCl42-
2. TiF62- and Cu2Cl2
3. CoF63- and NiCl42-
4. TiF62- and CoF63-

The correct order of decreasing second ionisation enthalpy of Ti(22), V(23), Cr(24) and Mn(25) is

1. Mn > Cr > Ti > V
2. Ti > V > Cr > Mn
3. Cr > Mn > V > Ti
4. V > Mn > Cr > Ti

Which one of the following ions is the most stable in aqueous solution? (At. No. Ti = 22, V = 23, Cr = 24, Mn = 25)

1. V3+
2. Ti3+
3. Mn3+
4. Cr3+

Identify the incorrect statement among the following:

1. Lanthanoid contraction is the accumulation of successive shrinkages.
2. As a result of lanthanoid contraction, the properties of 4d series of the transition elements have no similarities with the 5d series of elements.
3. Shielding power of 4f electrons is quite weak.
4. There is a decrease in the radii of the atoms or ions as one proceeds from La to Lu.

In which of the following pairs are both the ions coloured in aqueous solution? (At. no. : Sc = 21, Ti = 22, Ni = 28, Cu = 29, Co = 27)

1. Ni2+, Cu+
2. Ni2+, Ti3+
3. Sc3+, Ti3+
4. Sc3+, Co2+.

Copper sulphate dissolves in excess of KCN to give

1. Cu(CN)2
2. CuCN
3. [Cu(CN)4]3-
4. [Cu(CN)4]2-