Editing Chemical element (section)

=== Discovery and recognition of various elements ===
{{For timeline|Discovery of chemical elements}}

Ten materials familiar to various prehistoric cultures are now known to be elements: Carbon, copper, [[gold]], iron, lead, mercury, silver, sulfur, [[tin]], and [[zinc]]. Three additional materials now accepted as elements, [[arsenic]], [[antimony]], and [[bismuth]], were recognised as distinct substances before 1500 AD. [[Phosphorus]], [[cobalt]], and [[platinum]] were isolated before 1750.

Most of the remaining naturally occurring elements were identified and characterised by 1900, including:
* Such now-familiar [[Industry (manufacturing)|industrial]] materials as [[aluminium]], [[silicon]], [[nickel]], [[chromium]], magnesium, and tungsten
* Reactive metals such as [[lithium]], [[sodium]], potassium, and [[calcium]]
* The [[halogen]]s [[fluorine]], [[chlorine]], [[bromine]], and [[iodine]]
* Gases such as hydrogen, oxygen, nitrogen, helium, [[argon]], and [[neon]]
* Most of the [[rare-earth elements]], including [[cerium]], [[lanthanum]], [[gadolinium]], and [[neodymium]]
* The more common [[radioactive]] elements, including uranium, thorium, and [[radium]]

Elements isolated or produced since 1900 include:
* The three remaining undiscovered stable elements: [[hafnium]], [[lutetium]], and [[rhenium]]
* [[Plutonium]], which was first produced synthetically in 1940 by [[Glenn T. Seaborg]], but is now also known from a few long-persisting natural occurrences
* The three incidentally occurring natural elements ([[neptunium]], promethium, and technetium), which were all first produced synthetically but later discovered in trace amounts in geological samples
* Four scarce decay products of uranium or thorium (astatine, francium, [[actinium]], and [[protactinium]]), and
* All synthetic [[transuranic]] elements, beginning with [[americium]] and [[curium]]