What are 1A, 3B, and 7A examples of on the periodic table? 1 groups.
2 numbers
3 periods
4 rows

The correct answer is number, this is why

The periodic table is a type of table in which the element are systematically arranged on the basis of the atomic number.
The periodic table have the groups and periods. In the periodic table, there are 7 horizontal rows of elements are known as period and 18 vertical columns of elements are known as group.