f-block

The f-block of the periodic table of the elements consists of those elements whose atoms or ions have valence electrons in f-orbitals. Actual electronic configurations may be slightly different from what is predicted by the Aufbau principle. The elements are also known as inner transition elements, although that term is normally taken to include lutetium and lawrencium as well, which are part of the d-block.

All elements in the lanthanide series form M³⁺ ions. In aqueous solution the early lanthanides are surrounded by nine water molecules while the later lanthanides have a coordination number of 8. Cerium also forms compounds with the +4 oxidation state; Ce⁴⁺ has the very stable electronic configuration of the noble gas xenon. Ce(IV) is a strong oxidising agent. Eu²⁺ has the configuration [Xe]4f⁷ and is a strong reducing agent. The existence of Eu(II) is attributed to the stability of the half-filled f-shell.^[1]

See also

• Electron configuration

References

External links

• Images of f-orbitals
• Interactive f-orbital models can be found at this site:[1]