Periods are the horizontal rows in the periodic table of Mendeleev; this table contain 7 periods.
The periodic table has 7 periods on it.
The modern periodic table has seven periods.
See the link below
7The periodic table has 7 periods and 18 groups.
there are 7 periods in the periodic table118
there are 7 periods in the periodic table118
Horizontal rows are termed as periods. There are 7 periods in periodic table.
There are 7 periods in the modern periodic table.
In the periodic table of the elements there are 7 periods and 18 groups. The rows are called periods and columns are called groups. You may be getting confused by the lanthanides and actinides. These groups of elements are found in two rows at the bottom and seem to not be a part of the table. However, if you find and extended version of the table you will see that, technically, these two rows belong in Periods 6 and 7.
There are 7 periods in the modern periodic table.
7 periods and 18 groups are there on the modern periodic table.