The modern periodic table is an arrangement of all the elements known in accordance with their increasing atomic number and recurring chemical properties.
It is a tabular display of 118 chemical elements which consists of horizontal rows called periods and vertical columns are called groups.
All elements in a group have the same number of valance electrons, and in period elements have the same number of electron shells.
There are seven periods and eighteen groups in the modern periodic table.
Seventh period:
The 7th period has 32 elements from francium to oganesson (atomic number = 87 to 118).
The 7th period is considered an incomplete period.
It consists of elements whose properties have not been studied properly yet.