Why do we have a periodic table?

  Simply, the periodic table helps us to keep all known elements arranged in order. There are a hundred and eighteen elements discovered so far. Every element has a different set of chemical and physical properties. There are similarities in chemical and physical properties of many elements. There is a need to classify the elements properly so that we study all elements in an orderly fashion.

The periodic table contains elements arranged in increasing order of their atomic numbers. There are seven rows and eighteen columns in the periodic table. The rows are known as periods and the columns are known as groups. The periodic table is arranged such that there is a distinct variation of physical and chemical properties visible on it in the rows and columns. This makes it more useful as a source of classified information of elements.

The current periodic table was made by Dmitri Mendeleev in 1869. It was later on corrected by Henry Moseley in 1920. Before that there were many attempts made to classify the elements. Some of the notable attempts were the “Law of Octaves” by John Newland and “Law of Triads” by Doberiener. These all attempts were different methods used to classify elements. They aimed at arranging elements in a way that was most efficient and error free. However, each method had some errors that were not acceptable. So the attempts continued for decades until the modern periodic table was made by Dmitri Mendeleev and corrected by Henry Moseley.

The periodic table helps us to find the general properties of elements at a glance. It contains the atomic number, the atomic mass, and the symbol of elements. By looking at the position of an element in the periodic table, we are able to tell its physical and chemical characteristics to a high degree of accuracy. For example, all elements present in the first group will be metals, reactive elements, and will form ionic bonds with non metallic elements resulting in the formation of ionic compounds. They will be good conductors of electricity, and on dissolving them in water we will obtain their alkali and hydrogen gas.

Similarly, the elements of the seventeenth group of the periodic table will be nonmetals, reactive elements. They will form negative ions by gaining electrons, and they will react with metals to form ionic compounds.

Thus, we are able to guess the general chemical nature of an element from its position in the periodic table.