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 atomic numbers.
Periodic Table – Royal Society of Chemistry
https://www.rsc.org/periodic-tableThe Royal Society of Chemistry's interactive periodic table features history, alchemy, podcasts, videos, and data trends across the periodic table. Click the tabs at the top to explore each section. Use the buttons above to change your view of the periodic table and view Murray Robertson’s stunning Visual Elements artwork.