Group 4 element Group 4 element Group 4 is a group of elements in the periodic table. It contains the elements titanium (Ti), zirconium (Zr), hafnium (Hf) and rutherfordium (Rf). This group lies in the d-block of the periodic table. The group itself has not acquired a trivial name; it belongs to the broader grouping of the transition metals. The three Group 4 elements that occur naturally are titanium, zirconium and hafnium. The first three members of the group share similar properties; all three are hard refractory metals under standard conditions. However, the fourth element rutherfordium (Rf), has been synthesized in the laboratory;
History of the periodic table actinide series is the second row of the f-block (5f series). In both the actinide and lanthanide series, an inner electron shell is being filled. The actinide series comprises the elements from actinium to lawrencium. Seaborg's subsequent elaborations of the actinide concept theorized a series of superheavy elements in a transactinide series comprising elements from 104 to 121 and a superactinide series of elements from 122 to 153. History of the periodic table The periodic table is an arrangement of the chemical elements and are organized on the basis of their atomic numbers, electron configurations and recurring chemical properties. Elements