Group 12 element of 40 mg/day. Mercury and cadmium are toxic and may cause environmental damage if they enter rivers or rain water. This may result in contaminated crops as well as the bioaccumulation of mercury in a food chain leading to an increase in illnesses caused by mercury and cadmium poisoning. Group 12 element Group 12, by modern IUPAC numbering, is a group of chemical elements in the periodic table. It includes zinc (Zn), cadmium (Cd) and mercury (Hg). The further inclusion of copernicium (Cn) in group 12 is supported by recent experiments on individual copernicium atoms. Formerly this group was named
Periodic table to oganesson (95–118), occur only when synthesized in laboratories. Of the 94 naturally occurring elements, 83 are primordial and 11 occur only in decay chains of primordial elements. No element heavier than einsteinium (element 99) has ever been observed in macroscopic quantities in its pure form, nor has astatine (element 85); francium (element 87) has been only photographed in the form of light emitted from microscopic quantities (300,000 atoms). A "group" or "family" is a vertical column in the periodic table. Groups usually have more significant periodic trends than periods and blocks, explained below. Modern quantum mechanical theories of atomic