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 refers to red-violet as "purple"; in the Munsell color system, this color at the maximum chroma of 12 is called "Red-Purple". This convention is for chromatic purposes, since Red-Purple lies between violet and printer's magenta (the color regarded as magenta before the invention of the color electric magenta for computer displays). Red-violet is part of the red "analogous color group", which also includes magenta, red, red-orange, orange, gold, and yellow, i.e. those colors classified as "Warm colors", or colors that produces a feeling of warmth (as opposed to "cool colors"). The color that is the complement of red-violet, mint green,