Interactive periodic table with up-to-date element property data collected from authoritative sources. Look up chemical element names, symbols, atomic masses and other properties, visualize trends, or …

Explore how atomic radius changes with atomic number in the periodic table of elements via interactive plots.

Molecules, atoms, and ions of the stable isotopes of copper possess slightly different physical and chemical properties, and they commonly will be fractionated during physical, chemical, and biological …

Explore how atomic mass changes with atomic number in the periodic table of elements via interactive plots.

Molecules, atoms, and ions of the stable isotopes of hydrogen possess slightly different physical and chemical properties and they are commonly fractionated during physical, chemical, and biological …

Molecules, atoms, and ions of the stable isotopes of oxygen possess slightly different physical and chemical properties, and they commonly will be fractionated during physical, chemical, and biological …

Explore how density changes with atomic number in the periodic table of elements via interactive plots.

Carbon has seven isotopes. In 1961 the International Union of Pure and Applied Chemistry adopted the isotope carbon-12 as the basis for atomic weights. Carbon-14, an isotope with a half-life of 5715 …

For more information about the natural variations of the atomic weight of lead please read IUPAC Technical Report Variation of lead isotopic composition and atomic weight in terrestrial materials …

Molecules, atoms, and ions of the stable isotopes of calcium possess slightly different physical and chemical properties, and they commonly will be fractionated during physical, chemical, and biological …