The modern periodic table is also known as the long form of the periodic table or the extended form of the periodic table.
In this table, the elements are arranged in the order of increasing atomic numbers in such away that elements with similar properties fall in the same vertical column. These vertical columns are referred to as 'Groups '. There are eight groups, which are further sub-divided into eighteen sub-groups. There are 7 horizontal rows in the periodic table. These are called the periods.