QBManager

CHXII08:THE D- & F-BLOCK ELEMENTS

321678 Arrange ${Ce}^{3 +}, {La}^{3 +}, {Pm}^{3 +}$ and ${Yb}^{3 +}$ in the increasing order of their ionic radii :

1

{Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}

2

{Ce}^{3 +} < {Yb}^{3 +} < {Pm}^{3 +} < {La}^{3 +}

3

{Yb}^{3 +} < {Pm}^{3 +} < {La}^{3 +} < {Ce}^{3 +}

4

{Pm}^{3 +} < {La}^{3 +} < {Ce}^{3 +} < {Yb}^{3 +}

Explanation:

Due to lanthanide contraction, order will be ${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321679 Identify the wrong statement/s considering Lanthanoid contraction as the basis.
(i) As the size decreases covalent character increases. Therefore, ${La}_{2} O_{3}$ is more ionic and ${Lu}_{2} O_{3}$ is more covalent.
(ii) As the size decreases from $La$ to $Lu$ , stability of oxosalts also decreases.
(iii) Stability of complexes increases as the size of lanthanoids decreases.
(iv) Radii of $4 d a n d 5 d$ block elements will be almost same.
(v) Acidic character of oxides decreases from La to $Lu$ .

1

i

2 ii,iii

3

v

4 ii,iv

Explanation:

Acidic character of oxides increases from $La$ to $Lu$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321680 The trivalent ion having largest size in lanthanide series is

1

Ti

2

Zr

3

Hf

4 La

CHXII08:THE D- & F-BLOCK ELEMENTS

321681 The correct increasing order of ionic radii of the following $C e^{3 +}, L a^{3 +}, P m^{3 +} a n d Y b^{3 +} i s$

1

Y b^{3 +} < P m^{3 +} < C e^{3 +} < L a^{3 +}

2

C e^{3 +} < Y b^{3 +} < P m^{3 +} < L a^{3 +}

3

Y b^{3 +} < P m^{3 +} < L a^{3 +} < C e^{3 +}

4

P m^{3 +} < L a^{3 +} < C e^{3 +} < Y b^{3 +}

Explanation:

Due to lanthanide contraction, size of +3 ions decreases from ${La}^{3 +}$ to ${Lu}^{3 +}$ .
As the atomic number increases in order
${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +} . Thus,$ the correct order of ionic radii will be
${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321682 Select the INCORRECT statement.

1 Shielding effect of f-electrons are minimum out of all the electrons of N -shell.

2 As the f electrons increase,

Z_{eff}

on outer electron decreases in lanthanides.

3

Z_{eff}

on outer electron is

Lu > La

.

4 In lanthanide series, electrons are filled in (

n - 2) f

subshell.

CHXII08:THE D- & F-BLOCK ELEMENTS

321678 Arrange ${Ce}^{3 +}, {La}^{3 +}, {Pm}^{3 +}$ and ${Yb}^{3 +}$ in the increasing order of their ionic radii :

1

{Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}

2

{Ce}^{3 +} < {Yb}^{3 +} < {Pm}^{3 +} < {La}^{3 +}

3

{Yb}^{3 +} < {Pm}^{3 +} < {La}^{3 +} < {Ce}^{3 +}

4

{Pm}^{3 +} < {La}^{3 +} < {Ce}^{3 +} < {Yb}^{3 +}

Explanation:

Due to lanthanide contraction, order will be ${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321679 Identify the wrong statement/s considering Lanthanoid contraction as the basis.
(i) As the size decreases covalent character increases. Therefore, ${La}_{2} O_{3}$ is more ionic and ${Lu}_{2} O_{3}$ is more covalent.
(ii) As the size decreases from $La$ to $Lu$ , stability of oxosalts also decreases.
(iii) Stability of complexes increases as the size of lanthanoids decreases.
(iv) Radii of $4 d a n d 5 d$ block elements will be almost same.
(v) Acidic character of oxides decreases from La to $Lu$ .

1

i

2 ii,iii

3

v

4 ii,iv

Explanation:

Acidic character of oxides increases from $La$ to $Lu$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321680 The trivalent ion having largest size in lanthanide series is

1

Ti

2

Zr

3

Hf

4 La

CHXII08:THE D- & F-BLOCK ELEMENTS

321681 The correct increasing order of ionic radii of the following $C e^{3 +}, L a^{3 +}, P m^{3 +} a n d Y b^{3 +} i s$

1

Y b^{3 +} < P m^{3 +} < C e^{3 +} < L a^{3 +}

2

C e^{3 +} < Y b^{3 +} < P m^{3 +} < L a^{3 +}

3

Y b^{3 +} < P m^{3 +} < L a^{3 +} < C e^{3 +}

4

P m^{3 +} < L a^{3 +} < C e^{3 +} < Y b^{3 +}

Explanation:

Due to lanthanide contraction, size of +3 ions decreases from ${La}^{3 +}$ to ${Lu}^{3 +}$ .
As the atomic number increases in order
${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +} . Thus,$ the correct order of ionic radii will be
${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321682 Select the INCORRECT statement.

1 Shielding effect of f-electrons are minimum out of all the electrons of N -shell.

2 As the f electrons increase,

Z_{eff}

on outer electron decreases in lanthanides.

3

Z_{eff}

on outer electron is

Lu > La

.

4 In lanthanide series, electrons are filled in (

n - 2) f

subshell.

CHXII08:THE D- & F-BLOCK ELEMENTS

321678 Arrange ${Ce}^{3 +}, {La}^{3 +}, {Pm}^{3 +}$ and ${Yb}^{3 +}$ in the increasing order of their ionic radii :

1

{Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}

2

{Ce}^{3 +} < {Yb}^{3 +} < {Pm}^{3 +} < {La}^{3 +}

3

{Yb}^{3 +} < {Pm}^{3 +} < {La}^{3 +} < {Ce}^{3 +}

4

{Pm}^{3 +} < {La}^{3 +} < {Ce}^{3 +} < {Yb}^{3 +}

Explanation:

Due to lanthanide contraction, order will be ${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321679 Identify the wrong statement/s considering Lanthanoid contraction as the basis.
(i) As the size decreases covalent character increases. Therefore, ${La}_{2} O_{3}$ is more ionic and ${Lu}_{2} O_{3}$ is more covalent.
(ii) As the size decreases from $La$ to $Lu$ , stability of oxosalts also decreases.
(iii) Stability of complexes increases as the size of lanthanoids decreases.
(iv) Radii of $4 d a n d 5 d$ block elements will be almost same.
(v) Acidic character of oxides decreases from La to $Lu$ .

1

i

2 ii,iii

3

v

4 ii,iv

Explanation:

Acidic character of oxides increases from $La$ to $Lu$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321680 The trivalent ion having largest size in lanthanide series is

1

Ti

2

Zr

3

Hf

4 La

CHXII08:THE D- & F-BLOCK ELEMENTS

321681 The correct increasing order of ionic radii of the following $C e^{3 +}, L a^{3 +}, P m^{3 +} a n d Y b^{3 +} i s$

1

Y b^{3 +} < P m^{3 +} < C e^{3 +} < L a^{3 +}

2

C e^{3 +} < Y b^{3 +} < P m^{3 +} < L a^{3 +}

3

Y b^{3 +} < P m^{3 +} < L a^{3 +} < C e^{3 +}

4

P m^{3 +} < L a^{3 +} < C e^{3 +} < Y b^{3 +}

Explanation:

Due to lanthanide contraction, size of +3 ions decreases from ${La}^{3 +}$ to ${Lu}^{3 +}$ .
As the atomic number increases in order
${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +} . Thus,$ the correct order of ionic radii will be
${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321682 Select the INCORRECT statement.

1 Shielding effect of f-electrons are minimum out of all the electrons of N -shell.

2 As the f electrons increase,

Z_{eff}

on outer electron decreases in lanthanides.

3

Z_{eff}

on outer electron is

Lu > La

.

4 In lanthanide series, electrons are filled in (

n - 2) f

subshell.

CHXII08:THE D- & F-BLOCK ELEMENTS

321678 Arrange ${Ce}^{3 +}, {La}^{3 +}, {Pm}^{3 +}$ and ${Yb}^{3 +}$ in the increasing order of their ionic radii :

1

{Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}

2

{Ce}^{3 +} < {Yb}^{3 +} < {Pm}^{3 +} < {La}^{3 +}

3

{Yb}^{3 +} < {Pm}^{3 +} < {La}^{3 +} < {Ce}^{3 +}

4

{Pm}^{3 +} < {La}^{3 +} < {Ce}^{3 +} < {Yb}^{3 +}

Explanation:

Due to lanthanide contraction, order will be ${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321679 Identify the wrong statement/s considering Lanthanoid contraction as the basis.
(i) As the size decreases covalent character increases. Therefore, ${La}_{2} O_{3}$ is more ionic and ${Lu}_{2} O_{3}$ is more covalent.
(ii) As the size decreases from $La$ to $Lu$ , stability of oxosalts also decreases.
(iii) Stability of complexes increases as the size of lanthanoids decreases.
(iv) Radii of $4 d a n d 5 d$ block elements will be almost same.
(v) Acidic character of oxides decreases from La to $Lu$ .

1

i

2 ii,iii

3

v

4 ii,iv

Explanation:

Acidic character of oxides increases from $La$ to $Lu$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321680 The trivalent ion having largest size in lanthanide series is

1

Ti

2

Zr

3

Hf

4 La

CHXII08:THE D- & F-BLOCK ELEMENTS

321681 The correct increasing order of ionic radii of the following $C e^{3 +}, L a^{3 +}, P m^{3 +} a n d Y b^{3 +} i s$

1

Y b^{3 +} < P m^{3 +} < C e^{3 +} < L a^{3 +}

2

C e^{3 +} < Y b^{3 +} < P m^{3 +} < L a^{3 +}

3

Y b^{3 +} < P m^{3 +} < L a^{3 +} < C e^{3 +}

4

P m^{3 +} < L a^{3 +} < C e^{3 +} < Y b^{3 +}

Explanation:

Due to lanthanide contraction, size of +3 ions decreases from ${La}^{3 +}$ to ${Lu}^{3 +}$ .
As the atomic number increases in order
${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +} . Thus,$ the correct order of ionic radii will be
${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321682 Select the INCORRECT statement.

1 Shielding effect of f-electrons are minimum out of all the electrons of N -shell.

2 As the f electrons increase,

Z_{eff}

on outer electron decreases in lanthanides.

3

Z_{eff}

on outer electron is

Lu > La

.

4 In lanthanide series, electrons are filled in (

n - 2) f

subshell.

CHXII08:THE D- & F-BLOCK ELEMENTS

321678 Arrange ${Ce}^{3 +}, {La}^{3 +}, {Pm}^{3 +}$ and ${Yb}^{3 +}$ in the increasing order of their ionic radii :

1

{Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}

2

{Ce}^{3 +} < {Yb}^{3 +} < {Pm}^{3 +} < {La}^{3 +}

3

{Yb}^{3 +} < {Pm}^{3 +} < {La}^{3 +} < {Ce}^{3 +}

4

{Pm}^{3 +} < {La}^{3 +} < {Ce}^{3 +} < {Yb}^{3 +}

Explanation:

Due to lanthanide contraction, order will be ${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}$

CHXII08:THE D- & F-BLOCK ELEMENTS

321679 Identify the wrong statement/s considering Lanthanoid contraction as the basis.
(i) As the size decreases covalent character increases. Therefore, ${La}_{2} O_{3}$ is more ionic and ${Lu}_{2} O_{3}$ is more covalent.
(ii) As the size decreases from $La$ to $Lu$ , stability of oxosalts also decreases.
(iii) Stability of complexes increases as the size of lanthanoids decreases.
(iv) Radii of $4 d a n d 5 d$ block elements will be almost same.
(v) Acidic character of oxides decreases from La to $Lu$ .

1

i

2 ii,iii

3

v

4 ii,iv

Explanation:

Acidic character of oxides increases from $La$ to $Lu$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321680 The trivalent ion having largest size in lanthanide series is

1

Ti

2

Zr

3

Hf

4 La

CHXII08:THE D- & F-BLOCK ELEMENTS

321681 The correct increasing order of ionic radii of the following $C e^{3 +}, L a^{3 +}, P m^{3 +} a n d Y b^{3 +} i s$

1

Y b^{3 +} < P m^{3 +} < C e^{3 +} < L a^{3 +}

2

C e^{3 +} < Y b^{3 +} < P m^{3 +} < L a^{3 +}

3

Y b^{3 +} < P m^{3 +} < L a^{3 +} < C e^{3 +}

4

P m^{3 +} < L a^{3 +} < C e^{3 +} < Y b^{3 +}

Explanation:

Due to lanthanide contraction, size of +3 ions decreases from ${La}^{3 +}$ to ${Lu}^{3 +}$ .
As the atomic number increases in order
${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +} . Thus,$ the correct order of ionic radii will be
${Yb}^{3 +} < {Pm}^{3 +} < {Ce}^{3 +} < {La}^{3 +}$ .

CHXII08:THE D- & F-BLOCK ELEMENTS

321682 Select the INCORRECT statement.

1 Shielding effect of f-electrons are minimum out of all the electrons of N -shell.

2 As the f electrons increase,

Z_{eff}

on outer electron decreases in lanthanides.

3

Z_{eff}

on outer electron is

Lu > La

.

4 In lanthanide series, electrons are filled in (

n - 2) f

subshell.

Explanation:

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Question Bank Series

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