Final Answer:
There are 18 groups on the periodic table.
Step-by-step explanation:
The periodic table is organized into periods (horizontal rows) and groups (vertical columns). Each group, also known as a family, exhibits similar chemical properties due to the shared configuration of their outermost electron shells. As of my last knowledge update in January 2022, the periodic table consists of 18 groups, labeled from 1 to 18.
Groups 1 and 2, as well as 13 to 18, are referred to as the main-group elements. The transition metals, occupying the center of the table, are in groups 3 to 12. Elements within the same group share commonalities in their electron configurations, leading to similarities in chemical behavior. For example, Group 1 elements, known as alkali metals, have a single electron in their outermost shell and tend to form +1 cations.
It's important to note that new elements and discoveries might lead to adjustments in the periodic table. The information provided is based on the periodic table as of my last knowledge update. Students and researchers should refer to the most recent and reliable sources for the latest information on the periodic table's organization.