What are the vertical columns of the periodic table called?

Vertical columns of the periodic table are referred to as "groups" or "families." This terminology reflects the similarities in chemical properties and behavior of the elements within those columns. Elements that are in the same group typically have the same number of valence electrons, which plays a significant role in determining their chemical reactivity and bonding characteristics.

For example, the elements in group 1 are known as alkali metals, and they all exhibit similar properties, such as being highly reactive with water. Similarly, the elements in group 17, the halogens, share characteristics that make them distinct from other groups.

The other terms provided have different meanings in the context of the periodic table. "Periods" refers to the horizontal rows, while "categories" and "sections" are less commonly used in this context and do not specifically designate the vertical arrangement of elements.