Group 11 element can also lead to the accumulation of these metals in body tissue; the results are the irreversible but apparently harmless pigmentation conditions known as chrysiasis and argyria respectively. Due to being short lived and radioactive, roentgenium has no biological use but it is likely extremely harmful due to its radioactivity. Group 11 element Group 11, by modern IUPAC numbering, is a group of chemical elements in the periodic table, consisting of copper (Cu), silver (Ag), and gold (Au). Roentgenium (Rg) is also placed in this group in the periodic table, although no chemical experiments have yet been carried out to
Refractory metals cubic except rhenium which is hexagonal close-packed. Most physical properties of the elements in this group vary significantly because they are members of different groups. Creep resistance is a key property of the refractory metals. In metals, the starting of creep correlates with the melting point of the material; the creep in aluminium alloys starts at 200 °C, while for refractory metals temperatures above 1500 °C are necessary. This resistance against deformation at high temperatures makes the refractory metals suitable against strong forces at high temperature, for example in jet engines, or tools used during forging. The refractory metals show