Chemical element named mendelevium in honor of D.I. Mendeleev, the first to arrange the elements in a periodic manner. Most recently, the synthesis of element 118 (since named oganesson) was reported in October 2006, and the synthesis of element 117 (tennessine) was reported in April 2010. Ten materials familiar to various prehistoric cultures are now known to be chemical elements: Carbon, copper, gold, iron, lead, mercury, silver, sulfur, tin, and zinc. Three additional materials now accepted as elements, arsenic, antimony, and bismuth, were recognized as distinct substances prior to 1500 AD. Phosphorus, cobalt, and platinum were isolated before 1750. Most of the
Red-violet Red-violet Red-violet is a rich color of high medium saturation about 3/4 of the way between red and magenta, closer to magenta than to red. It is classified in color theory as one of the purple colors—a non-spectral color between red and violet that is a deep version of a color on the line of purples on the CIE chromaticity diagram. Both its saturation and brightness falling short of 100%, red-violet is not a pure chroma. There is a color of similar hue that, however, comes close to being a pure chroma: process magenta. The pure chroma color composed of