Chemical element by symbol, as well as ionization energies of the elements. The nuclides of stable and radioactive elements are also available as a list of nuclides, sorted by length of half-life for those that are unstable. One of the most convenient, and certainly the most traditional presentation of the elements, is in the form of the periodic table, which groups together elements with similar chemical properties (and usually also similar electronic structures). The atomic number of an element is equal to the number of protons in each atom, and defines the element. For example, all carbon atoms contain 6 protons in
Naming of chemical elements the 1970s (when the elements were discovered) to the 1990s, when the International Union of Pure and Applied Chemistry (IUPAC) created a tentative list of the element names for elements 104 to 109. The Americans, however, refused to agree with these names because seaborgium was not in the list. Thus, IUPAC reconsidered, and in 1996 named element 105 dubnium and element 106 seaborgium. When a pure element, comprising only one type of atom, nevertheless exists in multiple forms (allotropes) with different structure and properties, they are generally given different names; for example graphite and diamond are both forms of the