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
Block (periodic table) laboratory to help stabilize reactions that would usually proceed too quickly. As the atomic numbers increase, the elements become rarer. The second column from the right side of the periodic table, group 17, is the halogen family of elements. These elements are all just one electron shy of having full shells. Because they are so close to being full, they have the trait of combining with many different elements and are very reactive. Not all halogens react with the same intensity. Fluorine is the most reactive and combines with most elements from around the periodic table. As with other columns,