Chemistry · Ch 7 — Modern Periodic Table
Characteristics of f-Block Elements
Characteristics of f-Block Elements
All f-block elements are metals, arranged in two horizontal series placed below the main table: the lanthanoid series, running from ₅₈Ce to ₇₁Lu, and the actinoid series, running from ₉₀Th to ₁₀₃Lr. Each series takes its name from the element immediately preceding it in the main table — lanthanum, ₅₇La, and actinium, ₈₉Ac — both of which sit in group 3, of periods 6 and 7 respectively. The lanthanoids are also commonly called the 'rare earth elements'. Because the very last electron added to each of these elements enters the inner subshell (two shells below the valence shell), they are collectively called the INNER-TRANSITION elements, and — since that inner subshell is quite far from the elements' chemical 'surface' — the elements within each series display remarkably similar chemical properties to one another. Elements with atomic number beyond ₉₂U (uranium) are further dist …
Worked out. Worked example: two metals' chlorides are common colourless laboratory chemicals; one metal reacts vigorously with water, the other slowly — place each in its block and justify. Metal salts from the f-block and (with the exception of AlCl3) the p-block are not common laboratory chemicals, so the choice narrows to the s- and d-blocks. The metal reacting vigorously with water is an s-block metal (s-block metals are far more reactive, per section 7.4.1); the metal reacting only slowly is a d-block metal. The colourless nature of the less-reactive d-block metal's salt further implies its inner d-subshell is completely filled (partially-filled d-subshells tend to …