d- and f-Block Elements

Gadolinium belongs to 4f series. Its atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?

1. [Xe]4f9 5s1
2. [Xe]4f7 5d1 6s2
3. [Xe]4f6 5d2 6s2
4. [Xe]4f8 6d2

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+