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
SN 2002cx suggesting that SN 2002cx is similar to SN 1991T which also lacked such lines. This spectrum for SN 2002cx has a low expansion velocity measuring only ~6400 km s. This marked one way in which it was different from SN 1997br, as SN 1997br's expansion velocity was ~10,400 km s at the same point relative to its own B-band maximum. At the time of measurement SN 2002cx's expansion velocity was the lowest measured for an early time type Ia, Another spectrum taken on 2002 May 20, 1 day before B-band maximum light, showed little evolution from the one taken on