The d- and f- Block Elements Test

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The d- and f- Block Elements Test - 18

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Weekly Quiz Competition

Question 1
1 / -0

Transuranic elements begin with :

A
Np

B
Cm

C
Pu

D
U

Solution

The transuranic elements are the chemical elemnts with atomic numbers greater than 92 (the atomic number of Uranium). Neptunium is the first element of transuranic series with atomic number 93..
Question 2
1 / -0

Which of the following has smallest ionic radius ?

A
Nd$$^{3+}$$

B
Dy$$^{3+}$$

C
Lu$$^{3+}$$

D
Pm$$^{3+}$$

Solution

$$Lu^{3+}$$ is the last of the Lanthanides, so it's ions will have the smallest ionic radius due to Lanthanide contraction.
Question 3
1 / -0

Many Lanthanoid elements are used to prepare:

A
ceramic materials

B
water softener

C
superconducting materials

D
enzyme catalysts

Solution

Many Lanthanoid elements are used to prepare superconducting materials.

Examples include Lanthanum sesquicarbide superconductor $$La_2C_3$$. Gadolinium at very low temperatures becomes highly magnetic and may function as a superconductor.
Question 4
1 / -0

Lanthanoid contraction occurs because

A
the 4f electrons, which are gradually added, create strong shielding effect

B
the 4f orbitals are greater in size than the 3d and 3f orbitals

C
the 5f orbitals strongly penetrate into the 4f orbitals

D
the poor shielding effect of 4f electrons is coupled with increased attraction between the nucleus and the added electrons

Solution

Lanthanoid contraction occurs because the poor shielding effect of 4f electrons is coupled with increased attraction between the nucleus and the added electrons.
The atomic and ionic radii ($$M^{3+}$$ ions) of Lanthanide elements decrease with increase in atomic number.
Question 5
1 / -0

The atomic and ionic radii ($$M^{3+}$$ ions) of Lanthanide elements decrease with increase in atomic number. This effect is called as:

A
Lanthanoid contraction

B
Lanthanoid expansion

C
Actinoid contraction

D
none of these

Solution

The atomic and ionic radii ($$M^{3+}$$ ions) of Lanthanide elements decrease with increase in atomic number.
This effect is called Lanthanoid contraction. This is due to poor shielding of f electrons.
Question 6
1 / -0

The separation of Lanthanides by ion exchange method is based on:

A
basicity of the hydroxides

B
size of the ions

C
the solubility of their nitrates

D
oxidation state of the ion

Solution

The separation of Lanthanoids by ion-exchange method is based on the size of the ions.

Separation can also be attained by size exclusion or gel permeation chromatography.
Question 7
1 / -0

Which element among the Lanthanides has the smallest atomic radius ?

A
Cerium

B
Lutetium

C
Europium

D
Gadolinium.

Solution

Lutetium is the last element of the Lanthanides, so it will have the smallest ionic radius due to Lanthanide contraction.
Question 8
1 / -0

Which of the following cannot form oxo ion?

A
$$PuO_{2}^{+}$$

B
$$CeO_{2}^{+}$$

C
$$UO_{2}^{2+}$$

D
$$NpO_{2}^{+}$$

Solution

$$\displaystyle CeO_{2}^{+}$$ is not possible as cerium cannot form oxo ion.

Lanthanoids cannot form oxo ions while actinides can form oxo ions like $$\displaystyle UO^+, UO_2^+, PuO_2^{2+}$$.
Question 9
1 / -0

The Lanthanoids contraction relates to:

A
atomic radii

B
atomic as well as $$M^{3+}$$ radii

C
valence electrons

D
oxidation states.

Solution

The Lanthanoids contraction relates to atomic as well as $$M^{3+}$$ radii.
The atomic and ionic radii ($$M^{3+}$$ ions) of Lanthanide elements decrease with increase in atomic number. This effect is called Lanthanoid contraction. This is due to poor shielding of 4f electrons.
Question 10
1 / -0

The Lanthanoid contraction refers to decrease in the:

A
valence electrons of the Lanthanide series

B
ionic radius of the series

C
the density of the series

D
nuclear mass of the series

Solution

The Lanthanoid contraction refers to decrease in the ionic radius of the series.

It is a reduction in atomic/ionic size with increase in atomic number. This is due to poor shielding of 4f electrons.

Option B is correct.

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The d- and f- Block Elements Test - 18

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The d- and f- Block Elements Test - 18

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Question 1

Np

Cm

Pu

U

Solution

Question 2

Nd$$^{3+}$$

Dy$$^{3+}$$

Lu$$^{3+}$$

Pm$$^{3+}$$

Solution

Question 3

ceramic materials

water softener

superconducting materials

enzyme catalysts

Solution

Question 4

the 4f electrons, which are gradually added, create strong shielding effect

the 4f orbitals are greater in size than the 3d and 3f orbitals

the 5f orbitals strongly penetrate into the 4f orbitals

the poor shielding effect of 4f electrons is coupled with increased attraction between the nucleus and the added electrons

Solution

Question 5

Lanthanoid contraction

Lanthanoid expansion

Actinoid contraction

none of these

Solution

Question 6

basicity of the hydroxides

size of the ions

the solubility of their nitrates

oxidation state of the ion

Solution

Question 7

Cerium

Lutetium

Europium

Gadolinium.

Solution

Question 8

$$PuO_{2}^{+}$$

$$CeO_{2}^{+}$$

$$UO_{2}^{2+}$$

$$NpO_{2}^{+}$$

Solution

Question 9

atomic radii

atomic as well as $$M^{3+}$$ radii

valence electrons

oxidation states.

Solution

Question 10

valence electrons of the Lanthanide series

ionic radius of the series

the density of the series

nuclear mass of the series

Solution

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