The decrease in size from left to right in the actinoid series is greater and more gradual than that in the lanthanoid series due to:
 
1. 4f orbitals are penultimate
2. 4f orbitals have a greater shielding effect
3. 5f orbitals have a poor shielding effect
4. 5f orbitals have a greater shielding effect
Subtopic:  Lanthanoid & Actinoids Contraction |
 76%
From NCERT
NEET - 2022
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Zr (Z = 40) and Hf (Z = 72) have similar atomic and ionic radii because of: 

1. Lanthanoid contraction

2. Having similar chemical properties

3. Belonging to the same group

4. Diagonal relationship

Subtopic:  d-Block Elements- Properties & Uses | Lanthanoid & Actinoids Contraction |
 87%
From NCERT
NEET - 2021
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Identify the incorrect statement from the following:

1.  Zirconium and Hafnium have identical radii of 160 pm and 159 pm, respectively as a consequence of lanthanoid contraction.
2.  Lanthanoids reveal only +3 oxidation state.
3.  The lanthanoid ions other than the f0 type and the f14 type are all paramagnetic.
4.  The overall decrease in atomic and ionic radii from lanthanum to lutetium is called lanthanoid contraction.

Subtopic:  Lanthanoid & Actinoids Contraction |
 67%
From NCERT
NEET - 2020
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A pair among the following have nearly the same atomic radii:

(Numbers in the parenthesis are atomic numbers).

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

Subtopic:  f-Block Elements- Properties & Uses | Lanthanoid & Actinoids Contraction |
 90%
From NCERT
NEET - 2015
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The reason for the lanthanoid contraction is:

1. negligible screening effect of 'f' orbitals.

2. increasing nuclear charge.

3. decreasing nuclear charge.

4. decreasing screening effect.

Subtopic:  Lanthanoid & Actinoids Contraction |
 76%
From NCERT
AIPMT - 2014
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Actinoids exhibit more number of oxidation states than lanthanoids. It is because of: 
1. The greater metallic character of the lanthanoids than that of the corresponding actinoids.
2. More energy difference between 5f and 6d orbitals than that between 4f and 5d orbitals.
3. The lesser energy difference between 5f and 6d orbitals than that between 4f and 5d orbitals.
4. More active nature of the actinoids.
Subtopic:  d-Block Elements- Properties & Uses | f-Block Elements- Properties & Uses | Lanthanoid & Actinoids Contraction |
 79%
From NCERT
AIPMT - 2011
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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)

Subtopic:  Lanthanoid & Actinoids Contraction |
 80%
From NCERT
AIPMT - 2010
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Identify the incorrect statement among the following:

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

Subtopic:  Lanthanoid & Actinoids Contraction |
 84%
From NCERT
AIPMT - 2007
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Lanthanoids are:
 

1. 14 elements in the seventh period (atomic no. = 90 to 103) that are filling 5f sublevel.
2. 14 elements in the sixth period (atomic no. 58 to 71) that are filling 4f sublevel
3. 14 elements in the seventh period (atomic no. = 58 to 71) that are filling 4f sublevel
4. 14 elements in the sixth period (atomic no. 90 to 103) that are filling 4f sublevel
Subtopic:  Lanthanoid & Actinoids Contraction |
 83%
From NCERT
AIPMT - 2004
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