Periodic table - Wikipedia
https://en.wikipedia.org/wiki/Periodic_tableThe periodic table, also known as the periodic table of (the) (chemical) elements, is a tabular display of the chemical elements.It is widely used in chemistry, physics, and other sciences, and is generally seen as an icon of chemistry.It is a graphic formulation of the periodic law, which states that the properties of the chemical elements exhibit a periodic dependence on their …
Chemical element - Wikipedia
en.wikipedia.org › wiki › Chemical_elementMost of the remaining naturally occurring chemical elements were identified and characterized by 1900, including: Such now-familiar industrial materials as aluminium, silicon, nickel, chromium, magnesium, and tungsten Reactive metals such as lithium, sodium, potassium, and calcium The halogens ...