Cal: And what about these vertical columns? I mean, what does all of that mean? Mrs Roberts: Well, elements that have similar properties to each other are put into vertical columns called groups.

organizes all discovered chemical elements in rows (called periods) and columns (called groups) according to increasing atomic number. Scientists use the periodic table to quickly refer to information ...

Arranged by Atomic Number: Elements are arranged in order of increasing atomic number (number of protons) across periods (rows) and groups (columns). Periods: There are 7 periods (rows) in the table.