Chemical element chemical bonds, they form chemical compounds. Only a minority of elements are found uncombined as relatively pure minerals. Among the more common of such native elements are copper, silver, gold, carbon (as coal, graphite, or diamonds), and sulfur. All but a few of the most inert elements, such as noble gases and noble metals, are usually found on Earth in chemically combined form, as chemical compounds. While about 32 of the chemical elements occur on Earth in native uncombined forms, most of these occur as mixtures. For example, atmospheric air is primarily a mixture of nitrogen, oxygen, and argon, and
Cobalt poisoning One such example was seen in an experiment involving the effects of increased cobalt concentration on tomato plants. As the dosage of cobalt in the soil surrounding the plants increased, so too did the rate of necrosis of the leaves of the tomato plant. Over time this led to an inability of the plant to produce fruit and eventually the plant died. Cobalt poisoning Cobalt poisoning is intoxication caused by excessive levels of cobalt in the body. Cobalt is an essential element for health in animals in minute amounts as a component of Vitamin B. A deficiency of cobalt, which