Periodic Table of Elements - PubChem
pubchem.ncbi.nlm.nih.gov › periodic-tableThe creator of the periodic table, Dmitri Mendeleev, in 1869 began collecting and sorting known properties of elements, like he was playing a game, while traveling by train. He noticed that there were groups of elements that exhibited similar properties, but he also noticed that there were plenty of exceptions to the emerging patterns.
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 - Wikipedia
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 ...