What is the significance of the vertical columns of the periodic table? what is the significance of the horizontal rows?

Yes, horizontal rows are periods. "All of the elements in a period have a similar number of atomic orbitals. Each element in the top row (the principal time frame) has one orbital for its electrons. The greater part of the components in the second column (the second time frame) has two orbitals for their electrons. It goes down the occasional table that way. As of now, the most extreme number of electron orbitals or electron shells for any element is seven."

The vertical columns are groups. "The elements in a group have the same number of electrons in their outer orbital [and thus the same charge]. Every element in the first column (bunch one) has one electron in its external shell. Each element on the second segment (assemble two) has two electrons in the external shell. As you continue tallying the segments, you'll know what numbers of electrons are in the external shell.