Definition of Periodic Classification
The tabular classification or categorization of the chemical elements, with respect to their atomic number, configurations of electrons, and associated chemical properties is termed as Periodic Classification.
When a very large number of elements become known to scientists , it was felt that they must be arranged in a systematic order because a systematic classification provides a clear idea and information about the properties of elements and make it easier to predict the properties of different elements. This classification provides the inter-relationship of scientific facts. In old days, element were arranged in the ascending order of their atomic masses.
The Dalton’s atomic theory was the basis of classification of elements because according to the Dalton’s atomic theory
The atoms of different elements have different atomic masses.
The arrangement of the elements according to the particular order ( in a table known as Period Table as shown in the figure) is called as Periodic Classification.
There are total of 118 elements known so far and the discovery of new elements still continues. Every element has its own importance in the environment , some of them are useful while other are harmful. The harmful elements may also be useful in other way.
It becomes a necessity to study the chemical and physical properties of each of the elements present around us because every element is related to our life in some or other way. As the number is very large and there is possibility that more elements will be discovered, so it becomes very difficult to study each of them separately. We need to classify them in some groups according to their properties so that we can study them in group more easily and effectively. Periodic table is the tool which is used to classify the known elements in groups.
It helps us to undertake a systematic study of the various elements found in nature without which it would have been impossible for us to study all the elements in the table. With the help of periodic table a comparative study of the elements and their compounds can be done.
Periodic table also helps us to analyse the periodic trend in various properties such as ionisation potential, electron affinity, electronegativity etc.