The modern periodic table has been divided into:

The modern periodic table has been divided into seven periods – three short and four long.
The modern periodic table formulated by Moseley is formed of vertical columns called groups and horizontal rows called periods. There are 18 groups present in the periodic table with elements having similar properties belonging to the same groups. In the modern periodic table, 7 periods are present. Among these 7 periods, 3 are short and 4 are long.