d and f BLOCK ELEMENTS

What key difference between 5f and 4f orbitals is highlighted in the text?

• 5f orbitals are inherently more stable
• 5f orbitals are always completely filled
• 5f orbitals are less buried (less deeply located) than 4f orbitals
• 5f orbitals have inherently lower energy

How do the variations in metallic radii in actinoids compare to those in lanthanoids concerning structural effects?

• Lanthanoid variations are significantly greater
• They are essentially the same
• Actinoid variations are smaller
• Actinoid metallic radii variations are significantly greater, leading to more pronounced structural variability

Which element is identified as the first in the actinoid series where 5f orbital filling is formally considered to begin?

• Actinium (Ac)
• Thorium (Th)
• Protactinium (Pa)
• Uranium (U)

What is the relationship between the energy levels of 5f, 6d, and 7s orbitals in actinoids as stated in the text?

• 5f is much lower in energy than 6d and 7s
• 7s is much lower in energy than 5f and 6d
• 6d is much higher in energy than 5f and 7s
• They have comparable energies

Which actinoid ions are specifically mentioned as having a tendency to undergo hydrolysis?

• Only +3 ions
• Only +4 ions
• Both +3 and +4 ions
• Only +5 ions