Final answer:
The periodic table organizes elements based on atomic number and electron configuration. It consists of periods and groups that represent electron shells and valence electrons.
Step-by-step explanation:
The basic organizational feature of the periodic table of the elements is the arrangement of elements based on their atomic number and electron configuration.
In the periodic table, elements are organized into periods (rows) and groups (columns). The periods represent the number of electron shells an element has, while the groups represent the number of valence electrons.
For example, group 1 (the alkali metals) all have 1 valence electron, while group 18 (the noble gases) all have 8 valence electrons.
Learn more about Organizational features of the periodic table