The periodic table was built to show the relationships among the various elements. The periodic table was constructed in 1869 by Dmitri Mendeleev.
Elements are placed on the periodic table based on their atomic structure. Each row and column has specific characteristics. All the rows on the table are read left to right and each row is called a period. Each column on the table is called a group. Each group has the same number of electrons.
It is easy to find the number of electrons in the outer shell of each element on the table. Group one has one electron, group two has two and so on.