Period of the periodic table

What are the periods of the periodic table?

The periodic table of the elements consists of a total of seven periods. Each row of the periodic table represents a period. In contrast, each column forms a group of the periodic table.
Most of the lanthanides and actinides are shown under the seven periods. But they do not form their own periods, but belong to the 6th or 7th period. In addition, no chemical element from the 8th period has yet been detected. The existence of other elements is generally accepted.