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The discovery of the 118 chemical elements known to exist today is presented here in chronological order.

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André-Louis Debierne had previously reported the discovery of a new element actinium that was supposedly similar to titanium and thorium; the elements were mistakenly identified as being identical and Debierne's name was chosen, even though in retrospect Debierne's substance could not have included much actual element 89Welsbach proved that the old ytterbium also contained a new element, which he named cassiopeium.Urbain also proved this simultaneously, but his samples were very impure and only contained trace quantities of the new element.It was originally obtained as a native metal and later from the smelting of ores.Earliest estimates of the discovery of copper suggest around 9000 BCE in the Middle East.It was one of the most important materials to humans throughout the Chalcolithic and Bronze Ages.

Copper beads dating from 6000 BCE have been found in Çatal Höyük, Anatolia The oldest known iron objects used by humans are some beads of meteoric iron, made in Egypt in about 4000 BCE.Gregor found an oxide of a new metal in ilmenite; Martin Heinrich Klaproth independently discovered the element in rutile in 1795 and named it.The pure metallic form was only obtained in 1910 by Matthew A. Río found the metal in vanadinite but retracted the claim after Hippolyte Victor Collet-Descotils disputed it.Joseph Priestley also prepared this new air by 1774, but only Lavoisier recognized it as a true element; he named it in 1777.He showed that the air in which animals had breathed, even after removal of the exhaled carbon dioxide, was no longer able to burn a candle.In 1811 Louis-Joseph Gay-Lussac and Louis-Jacques Thénard probably prepared impure silicon, Antoine Lavoisier predicted in 1787 that alumine is the oxide of an undiscovered element, and in 1808 Humphry Davy tried to decompose it. Hans Christian Ørsted was the first to isolate metallic aluminium in 1825.