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-crowned hummingbird Violet-crowned hummingbird The violet-crowned hummingbird ("Amazilia violiceps") is a medium-sized hummingbird. It is 10 cm long and weighs approximately 5 g. The bird is best distinguished by its violet-colored cap, from where it gets its name. Adults are colored predominantly a dark olive green for their upperparts and tail. The underparts are predominantly white. The bill of the male is straight and very slender. It is red in coloration, and shows a black tip. The female is less colorful than the male. The breeding habitat is in arid scrub of southeastern Arizona in the United States to southwestern Mexico, (the