Question

What are the horizontal rows of the periodic table called?

A) cycles
B) periods
C) groups
D) columns

Answer 1

The horizontal rows on the periodic table are known as periods, which are seven in total, sequentially numbered from 1 to 7.

Step-by-step explanation:

The horizontal rows on the periodic table are called periods. There are seven periods, numbered from 1 at the top to 7 at the bottom. Each period corresponds to the filling of a different principal energy level of electrons, which shapes the structure of the table and the properties of the elements within each period.