Long Form of Periodic Table: Since the time of Mendeleev, many forms of the periodic table have been suggested from time to time. The most simple and widely accepted of all these forms is the Extended or Long Form of periodic table. The main features of the long form of periodic table are mentioned below- Groups- There are 18 vertical columns in the periodic table which form 16 groups in all, one group (Group VIII) being divided into three families occupying three vertical columns. The groups are numbered I – A to VII – A, I – B to VII … Continue reading Long Form of Periodic Table