D and F - Block Elements Test

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D and F - Block Elements Test - 8

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Weekly Quiz Competition

Question 1
4 / -1

Arrange Ce³⁺, La³⁺, Pm³⁺, and Yb³⁺ in increasing order of their ionic radius –
[AIEEE-02]

A
Yb³⁺< Pm³⁺ < Ce³⁺< La³⁺

B
Ce³⁺>Yb³⁺< Pm³⁺ < La³⁺

C
Yb³⁺>Pm³⁺< La³⁺< Ce³⁺

D
Pm³⁺ < La³⁺< Ce³⁺< Yb³⁺

Solution

The correct answer is Option A.
Atomic and ionic radii of Lanthanides decrease from La to Lu.
Their order of ionic radii:
Yb³⁺ < Pm3⁺< Ce³⁺ < La³⁺
Question 2
4 / -1

What would happen when a solution of potassium chromate is treated with an excess of dilute nitric acid -
[AIEEE-03]

A
Cr³⁺ and Cr₂O₇^2_are formed

B
Cr₂O₇^2_and H₂O are formed

C
Cr₂O₇^2_is reduced to +3 state of Cr

D
Cr₂O₇^2_ is oxidised to +7 state of Cr

Solution

The correct answer is Option B.

A solution of potassium chromate, when treated with an excess of dilute nitric acid doesn't oxidize nitric acid as N is already present in its maximum oxidation state (+5). The products formed are Cr2O₇^2- and H₂O.
Question 3
4 / -1

The radius of La³⁺ is 1.06 Å, which of the following given values will be closest to the radius of Lu³⁺ (At no. of Lu = 71, La = 57) –
[AIEEE-03]

A
1.6 Å

B
1.4 Å

C
1.06 Å

D
0.85 Å

Solution

The correct answer is Option D.
Due to lanthanide contraction, the ionic radii of Ln3+ (lanthanide ions) decreases from La3+ to Lu3+. Thus the lowest value (here 0.85Å) is the ionic radius of Lu3+.
Question 4
4 / -1

Cerium (Z = 58) is an important member of the lanthanoids. Which of the following statement about cerium is incorrect -
[AIEEE-04]

A
Cerium (IV) acts as an oxidising agent

B
The +3 oxidation state of cerium is more stable than the +4 oxidation state

C
The +4 oxidation state of cerium is not known in solutions

D
The common oxidation states of cerium are +3 and +4

Solution

The incorrect statement about the Cerium is only a C option.
C: The +4 oxidation state of cerium is not known in solutions [ Incorrect ]
As +4 oxidation state is common for the Cerium.
The correct statement about the Cerium are as follows:
A: The common oxidation states of Cerium are +3, and +4.
B : The +3 oxidation state of the Cerium is more stable than the +4 oxidation state.
D: Cerium (IV) acts as an oxidising agent
Question 5
4 / -1

Excess of KI reacts with CuSO₄ solution and then Na₂S₂O₃solution is added to it. Which of the statements is incorrect for this reaction -
[AIEEE-04]

A
Evolved I₂ is reduced

B
CuI₂ is formed

C
Na₂S₂O₃is oxidised

D
Cu₂I₂ is formed

Solution

The correct answer is option B
It is given that an excess of KI reacts with CuSO₄ solution and then Na2S2O3 is added to it. This is hypo test and reactions are as follows:
2CuSO₄ + 4KI → 2K₂SO₄ + 2CuI+I₂
2Na₂S₂O₃ + I2→ Na₂S₄O₆ + 2NaI
CuI2 is not formed according to the following reaction.
2CuI₂(unstable) → 2CuI+I₂
Hence, the statement in option B is incorrect.
Question 6
4 / -1

Calomel on reaction with NH₄OHgives –
[AIEEE-04]

A
HgNH₂Cl

B
NH₂–Hg–Hg–Cl

C
Hg₂O

D
HgO

Solution

The correct answer is option A
When calomel (H_g2Cl₂) reacts with NH4OH solution, the compound formed is [HgO.Hg(NH₂)Cl]. It is black in colour.
Hg₂Cl₂+2NH₄OH→[HgO.Hg(NH₂)Cl]↓+NH₄Cl+2H₂O
Question 7
4 / -1

The lanthanoid contraction is responsible for the fact that -
[AIEEE-05]

A
Zr and Y have about the same radius

B
Zr and Nb have similar oxidation state

C
Zr and Hf have about the same radius

D
Zr and Zn have similar oxidation state

Solution

The correct answer is Option C
Due to poor shielding effect of 4f electrons the nucleus experiences more effective nuclear charge and results in contraction which is known as lanthanide contraction. Due to lanthanide contraction 5th and 6th period transition series have approximately the same size. Therefore, lanthanide contraction is responsible for Zr and Hf having the same size.
Question 8
4 / -1

Lanthanoid contraction is caused due to –
[AIEEE-06]

A
The same effective nuclear charge from Ce to Lu

B
The imperfect shielding on outer electrons by 4f electrons from the nuclear charge

C
The appreciable shielding on outer electrons by 4f electrons from the nuclear charge

D
The appreciable shielding on outer electrons by 5d electrons from the nuclear charge

Solution

The elements in the Lanthanide series are La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.
In Lanthanides (Ce−Lu), the atomic and ionic radii decrease steadily. This steady decrease in atomic and ionic radii is known as Lanthanide Contraction.
The contraction is due to the fact that f−orbitals are not capable of providing effective shielding for the valence electrons from the nuclear attraction.
Question 9
4 / -1

Identify the incorrect statement among the following -
[AIEEE-07]

A
d-block elements show irregular and erratic chemical properties among themselves

B
La and Lu have partially filled d-orbitals and no other partially filled orbitals

C
The chemistry of various lanthanoids is very similar

D
4f and 5f-orbitals are equally shielded

Solution

The correct answer is option D
4f and 5f belongs to different energy levels, hence the shielding effect on them is not the same. Shielding of 4f is more than 5f.
Question 10
4 / -1

The actinoids exhibits more number of oxidation states in general than the lanthanoids. This is because
[AIEEE-07]

A
The 5f-orbitals are more buried than the 4f-orbitals

B
There is a similarly between 4f-and-5f in the their angular part of the wave function

C
The actinoids are more reactive than the lanthanoids

D
The 5f-orbitals extend further from the nucleus than the 4f-orbitals

Solution

The correct answer is option D
Lanthanoids primarily show three oxidation states (+2, +3, +4). Among these oxidation states, +3 state is the most common. Lanthanoids display a limited number of oxidation states because the energy difference between 4f, 5d and 6s orbitals is quite large. On the other hand, the energy difference between 5f, 6d and 7s orbitals is very less. Hence, actinoids display a large number of oxidation states.
Question 11
4 / -1

In context with the transition elements, which of the following statements is incorrect?
[AIEEE-09]

A
In the highest oxidation states, the transition metal show basic character and form cationic complexes.

B
In the highest oxidation states of the first five transition elements (Sc to Mn), all the 4s and electrons are used for bonding.

C
Once the d⁵ configuration is exceeded, the tendency to involve all the 3d electrons in
bonding decreases.

D
In addition to the normal oxidation states, the zero oxidation state is also shown by these elements in complexes.

Solution

The correct answer is option A
As oxidation state increases, electronegativity increases thus acidic characteristic increases not basic.
Question 12
4 / -1

Knowing that the Chemistry of lanthanoids (Ln) is dominated by its +3 oxidation state, which of the following statements is incorrect ?
[AIEEE-09]

A
The ionic sizes of Ln (III) decrease in general with increasing atomic number.

B
Ln (III) compounds are generally colourless.

C
Ln (III) hydroxides are mainly basic in character.

D
Because of the large size of the Ln (III)ions the bonding in its compounds is predominantly ionic in character.

Solution

The correct answer is option B
Ln(III) compounds are coloured due to the f−f transitions in the lanthanide but the colour is fainter as compared to the d−d transitions in transition metals.
Question 13
4 / -1

Iron exhibits + 2 and +3 oxidation states. Which of the following statements about iron is incorrect?
[AIEEE-2012]

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 hydrolyzed than the corresponding ferric compounds.

Solution

The correct answer is Option D.
Ferrous oxide is more basic in nature than ferric oxide. Ferrous compounds are relatively more ionic than the corresponding ferric compounds. Ferrous compounds are less volatile than the corresponding ferric compounds as ferrous compounds are more ionic.

But ferric compounds are more easily hydrolyzed than the corresponding ferrous compounds due to their more positive charge.

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D and F - Block Elements Test - 8

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D and F - Block Elements Test - 8

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Question 1

Yb3+ < Pm3+ < Ce3+ < La3+

Ce3+ > Yb3+ < Pm3+ < La3+

Yb3+ > Pm3+ < La3+ < Ce3+

Pm3+ < La3+ < Ce3+ < Yb3+

Solution

Question 2

Cr3+ and Cr2O72_ are formed

Cr2O72_ and H2O are formed

Cr2O72_ is reduced to +3 state of Cr

Cr2O72_ is oxidised to +7 state of Cr

Solution

Question 3

1.6 Å

1.4 Å

1.06 Å

0.85 Å

Solution

Question 4

Cerium (IV) acts as an oxidising agent

The +3 oxidation state of cerium is more stable than the +4 oxidation state

The +4 oxidation state of cerium is not known in solutions

The common oxidation states of cerium are +3 and +4

Solution

Question 5

Evolved I2 is reduced

CuI2 is formed

Na2S2O3 is oxidised

Cu2I2 is formed

Solution

Question 6

HgNH2Cl

NH2–Hg–Hg–Cl

Hg2O

HgO

Solution

Question 7

Zr and Y have about the same radius

Zr and Nb have similar oxidation state

Zr and Hf have about the same radius

Zr and Zn have similar oxidation state

Solution

Question 8

The same effective nuclear charge from Ce to Lu

The imperfect shielding on outer electrons by 4f electrons from the nuclear charge

The appreciable shielding on outer electrons by 4f electrons from the nuclear charge

The appreciable shielding on outer electrons by 5d electrons from the nuclear charge

Solution

Question 9

d-block elements show irregular and erratic chemical properties among themselves

La and Lu have partially filled d-orbitals and no other partially filled orbitals

The chemistry of various lanthanoids is very similar

4f and 5f-orbitals are equally shielded

Solution

Question 10

The 5f-orbitals are more buried than the 4f-orbitals

There is a similarly between 4f-and-5f in the their angular part of the wave function

The actinoids are more reactive than the lanthanoids

The 5f-orbitals extend further from the nucleus than the 4f-orbitals

Solution

Question 11

In the highest oxidation states, the transition metal show basic character and form cationic complexes.

In the highest oxidation states of the first five transition elements (Sc to Mn), all the 4s and electrons are used for bonding.

Once the d5 configuration is exceeded, the tendency to involve all the 3d electrons in bonding decreases.

In addition to the normal oxidation states, the zero oxidation state is also shown by these elements in complexes.

Solution

Question 12

The ionic sizes of Ln (III) decrease in general with increasing atomic number.

Ln (III) compounds are generally colourless.

Ln (III) hydroxides are mainly basic in character.

Because of the large size of the Ln (III)ions the bonding in its compounds is predominantly ionic in character.

Solution

Yb³⁺< Pm³⁺ < Ce³⁺< La³⁺

Ce³⁺>Yb³⁺< Pm³⁺ < La³⁺

Yb³⁺>Pm³⁺< La³⁺< Ce³⁺

Pm³⁺ < La³⁺< Ce³⁺< Yb³⁺

Cr³⁺ and Cr₂O₇^2_are formed

Cr₂O₇^2_and H₂O are formed

Cr₂O₇^2_is reduced to +3 state of Cr

Cr₂O₇^2_ is oxidised to +7 state of Cr

Evolved I₂ is reduced

CuI₂ is formed

Na₂S₂O₃is oxidised

Cu₂I₂ is formed

HgNH₂Cl

NH₂–Hg–Hg–Cl

Hg₂O

Once the d⁵ configuration is exceeded, the tendency to involve all the 3d electrons in
bonding decreases.