Groups

A vertical column of the periodic table is called a Group. A group consists of a series of elements having similar configuration of the outer energy shell. There are eighteen vertical columns in the long form of periodic table. According to IUPAC, these groups are now numbered from 1 to 18. It may be noted that the elements belonging to the same group are said to constitute a FAMILY. For example, elements of group17 constitute halogen family. Similarly group 16 constitute Oxygen family or Chalcogen Family.