d and f BLOCK ELEMENTS

What happens to the size of the 4f orbitals as the atomic number increases within the lanthanide series?

• Remains constant
• Increases steadily
• Fairly regular decrease
• Increases then decreases

Which pair of elements illustrates the effect of lanthanoid contraction by having very similar atomic radii?

• Scandium (Sc) and Yttrium (Y)
• Titanium (Ti) and Zirconium (Zr)
• Niobium (Nb) and Tantalum (Ta)
• Zirconium (Zr) and Hafnium (Hf)

What is a direct consequence of the decrease in metallic radius and increase in atomic mass in the transition series?

• Decrease in density
• Increase in volume
• Increase in density
• No change in density

Compared to the shielding provided by d-electrons, how effective is the shielding provided by 4f electrons?

• More effective
• Equally effective
• Less effective
• It depends on the element

How does the lanthanoid contraction affect the atomic radii of elements in the second and third transition series?

• It increases them significantly
• It decreases them significantly
• It makes their radii very similar
• It has no effect