Group of the periodic table
In chemistry, a group of the periodic table is understood to mean any column of the periodic table . All elements of a group have the same number of valence electrons and therefore have similar chemical properties . Groups with particularly similar properties are also referred to as element families ; this mainly concerns the alkali and alkaline earth metals as well as the halogens .
There are a total of 18 groups, of which eight (groups 1, 2 and 13–18) are called main groups and ten (groups 3–12) are called subgroups ; the transition metals are in the subgroups . Several groups are combined into blocks .
Names of the groups
Because the elements in a group have similar chemical properties , some groups have special names. The best-known groups are in the first and second columns: alkali metals and alkaline earth metals. In the seventh and eighth columns you can find the halogens and noble gases.
IUPAC Convention (old)
The old IUPAC number ( International Union of Pure and Applied Chemistry ) referred to the long-period system. It was common in America; A stood for the left and B for the right side of the periodic table.
IUPAC Convention (current)
The numbering of the groups with Arabic numerals (1 to 18) follows the valid IUPAC convention and should replace the use of the CAS and the old IUPAC conventions.
|Main group / sub group
|Alkali metals and hydrogen
|1st main group
|Alkaline earth metals
|2nd main group
|Boron group / earth metals
|3rd main group
|Carbon-silicon group / tetrele
|4th main group
|Nitrogen-phosphorus group / pnictogens
|5th main group
|Chalcogens / oxygen group / ore formers
|6th main group
|Halogens / fluorine groups / salt formers
|7th main group
|Noble gases / helium group
|8. Main group
The not yet found elements with the atomic number 122 to 153 form a group that is called superactinoids after Glenn T. Seaborg . With them the 5g and 6f orbitals are filled. All of these elements are likely to be unstable and radioactive.