Explanation:
The columns of the periodic table represent the groups in the periodic table. They are 18 columns in the periodic table therefore there are 18 groups. Each group most important property is the valence electrons. The valence electrons is the number of electrons in their outer shell. Because of their valence electrons, each element in the group share similar chemical and physical properties.
For example, all elements in the 18 th column (group number 18) are called inert gases. They all conduct electricity and they are fluorescent, odorless and colorless.
