The first person to recognize the similarities among the basic elements existing in nature was a German chemist, Johann Wolfgang Döbereiner, in 1829. First devised by Antoine Lavoisier in 1789, systematically updated by Johann Wolfgang, and later by many others, the final of the periodic table version was created by the Russian chemist Dmitri Mendeleev in 1869. The table was created with the intention of classifying and illustrating the recurring (periodic) trends or similarities in the properties of elements. The table lists confirmed details of 116 established elements as of 2005. The table is followed widely across faculties in physics, biology, engineering and related industries.
The table lists elements depending on similarities in their chemical properties and arranged according to their atomic mass. The elements were listed in an increasing order based on the number of protons in the elements’ nucleus. The modern table has elements listed horizontally based on the increasing number of electrons in the outer shell and vertically based on the increasing number of protons in the nucleus. Each element is listed by its own symbol and atomic number. Detailed tables include information pertaining to the element such as abbreviated electron configuration, electronegativity and most common valence numbers.
The table comprises of 94 elements occurring naturally on earth and 22 synthetic elements, artificially produced in particle accelerators. The table is used to predict the variance in the chemical properties of an element according to its location in the table. The differences in the characteristics vary more while reading vertically along the columns than moving horizontally across the rows.
Most elements are grouped into “families” based on the variance in their atomic structures. Modern quantum theories suggest elements having similar electron configurations in their valence shell exist in the same group and possess similar chemical properties. For e.g., Fluorine, Chlorine, Bromine and Iodine exist under the family of halogens. The groups of families named are Alkali metals, Alkali earth metals, Transition metals, Halogens and Noble gases. | 
