F Block Elements : The f block elements are arranged in two chemical series in the periodic table: the 4f block is named after lanthanides or rare earth elements, and the 5f block is named after actinides or actinides. Lanthanides, or 4f block elements, comprise the first inner transition metals series in chemistry, while actinides comprise the second inner transition metals series.
The electron arrangement of the f block elements (actinium and lanthanum) is a result of filling electrons in deep-seated 4f and 5f orbitals with increasing atomic numbers. Trivalent oxidation numbers or states, which are stable or common oxidation states, are present in all f block elements. Achieve JEE excellence with PW JEE Online Course . Join now to fulfill your engineering dreams!Properties | Lanthanides | Actinides |
Electronic Configuration | 4f1-145p65d0-16s2 | 5f1-146s26p66d0-17s2 |
Orbital for Last Electron | 4f | 5f |
Basic Nature of Compounds | Less basic | More basic |
Radioactivity | Non-radioactive (except promethium) | Radioactive |
Common Oxidation States | Usually +3, sometimes +4 and +2 | Typically, +3 |
Complex Formation | Slow to form complexes | Form complexes readily |