d and f BLOCK ELEMENTS

What is the main factor contributing to the wide range of oxidation states observed in actinoids?

• High atomic masses
• Strong metallic bonding
• The 5f, 6d, and 7s energy levels are comparable
• Complete filling of 5f orbitals

What is the primary reason for the greater contraction observed in actinoids compared to lanthanoids?

• Greater nuclear charge
• Better shielding by 5f electrons
• Poor shielding by 5f electrons
• Smaller atomic masses

What phenomenon, similar to lanthanoid contraction, is observed in actinoids?

• Actinoid expansion
• Lanthanoid expansion
• Actinoid contraction
• Poor shielding effect

Why are the 5f electrons in actinoids able to participate more in bonding compared to 4f electrons in lanthanoids?

• Because 5f orbitals are completely filled
• Because 5f electrons are always lost first
• Because 5f orbitals are not as buried as 4f orbitals
• Because 5f electrons have lower energy than 4f electrons

What is the general electronic configuration believed for actinoids?

• 5f¹⁴ 7s² for all
• 6d² 7s² for all
• 7s² with variable occupancy of 5f and 6d subshells
• 4f¹⁴ 5d¹⁰ 7s² for all