d and f BLOCK ELEMENTS Quiz

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• High atomic masses of actinoids
• Strong metallic bonding characteristics
• The energy levels of 5f, 6d, and 7s orbitals are relatively close to each other
• Complete filling of the 5f orbitals

• Actinoids have larger atomic numbers
• Actinoids have better nuclear charge screening
• The 5f electrons provide less effective shielding of outer electrons from the increasing nuclear charge
• Actinoids have smaller initial ionic radii

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

• 5f orbitals are completely filled
• 5f electrons are always lost first in reactions
• 5f orbitals are less effectively shielded and more spatially accessible than 4f orbitals
• 5f electrons have inherently lower energy levels