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
Violet (color) sense for any color between blue and red). In color theory, a purple is a color along the line of purples on the CIE chromaticity diagram and excludes violet. Violet light from the rainbow, which can be referred as spectral violet, has only short wavelengths. Violet objects are objects that reflect violet light. Objects reflecting spectral violet often appear dark, because human vision is relatively insensitive to those wavelengths. Monochromatic lamps emitting spectral-violet wavelengths can be roughly approximated by the color shown below as "electric violet". The earliest violet pigments used by humans, found in prehistoric cave paintings, were made