Group 4 element doses and does not play any natural role inside the human body. Zirconium powder can cause irritation, but only contact with the eyes requires medical attention. OSHA recommendations for zirconium are 5 mg/m time weighted average limit and a 10 mg/m short-term exposure limit. Only limited data exists on the toxicology of hafnium. 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
History of the periodic table in an obscure Russian journal and then republished in a German journal, "Zeitschrift für Chemie". In it, Mendeleev stated that: Scientific benefits of Mendeleev's table Unknown to Mendeleev, a German chemist, Lothar Meyer, was also working on a periodic table. Although his work was published in 1864, and was done independently of Mendeleev, few historians regard him as an equal co-creator of the periodic table. Meyer's table only included twenty-eight elements, which were not classified by atomic weight, but by valence, and he never reached the idea of predicting new elements and correcting atomic weights. A few months after Mendeleev