A pair among the following have nearly the same atomic radii:
(Numbers in the parenthesis are atomic numbers).
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.
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. |
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)
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. |