The periodic table is useful because it identifies and arranges all known elements in an informative manner. Elements are arranged into periods and families. The elements in each family or period may have similar or dissimilar physical and chemical properties.
The horizontal rows in the periodic table are referred to as periods. The period number of any element indicates the number of energy levels it contains. The number of electrons decreases as one moves up the periodic table and vice versa. There are seven period of naturally occurring elements on the table.
The vertical columns of elements on the table are known as groups. There are 18 groups in the periodic table, and the elements in each group have the same number of electrons in their outermost energy levels. The outermost electrons are called valence electrons and are involved in chemical bonds with other elements. This feature helps scientists and students predict the types of chemical reactions that are likely to occur when one element reacts with another.
The periodic table also provides all the essential information needed to balance chemical equations. It has each element’s atomic number, which is also its atomic mass. Additionally, the elements' atomic charges can be determined according to the elements' groups.