Actinides: general trends
f-Block Elements · Chemistry
Study notes
Uranium shows +3 to +6 but lanthanides mostly +3. Explain. Step 1: 5f orbitals extend further out than 4f — less buried, more available for bonding. Step 2: 5f, 6d, 7s energies are close → electrons from all three can participate. Step 3: So U loses up to 6 electrons: UO₂²⁺ (uranyl, +6) is stable. Step 4: Later actinides (Am onwards) behave more like lanthanides (+3 dominates) as 5f buries deeper.