Elements are entities of the matter which have different chemical and physical properties. Almost all the elements exist in the form of compounds in which different elements are joined in definite ratios and this ratio is always constant.
Water is made up of 2 atoms of hydrogen element and 1 element of oxygen. No matter from where you collect the water, it shall have the same composition.
But notwithstanding the differences, they form groups which are like the siblings. They are similar and dissimilar at the same time meaning that they follow a progression of physical and chemical properties.
For example. there are elements called alkali metals which form hydroxides having high pH solutions in water. Only difference is that pH will be different for hydroxides of different metals.
From the days of alchemy, chemists were fascinated by the elements and trying to group them in such a way that elements closer in nature to one another come in one cluster. It was also observed that by placing the elements in rows and columns, moving along a row, at the end of the row, the next element shall be like the first element of the previous row.
They tried to understand why sometimes atoms of different elements have strong affinity for each other whereas other atoms hate each other and have to coerced to react with one another.
On the earth’s surface and subsurface, elements are found in the form of compounds and constitute the minerals. Sand or silica is composed of silicon and oxygen atoms and bauxite is made up from the combination of aluminum, oxygen and hydrogen atoms.
The lifetime endeavor of many chemists was divide the elements in groups in such a way that properties of elements adjacent to one another can be predicted by looking at their location. They were trying to place them on the paper with their locations in definite arrangements.
After so much efforts, it was the genius of Dmitri Ivanovich Mendeleev, a 19th Century Russian chemist, who came up with arrangement of 63 elements known in his time based on the periodicity of the properties. He placed them in rows called periods and columns called groups and the periodic table of elements was born. The name periodic indicates the periodicity in the properties of the elements. In his time, the concept of atomic structure of atoms was unknown. No one knew the atomic numbers. But in the end when these concepts became popular, the foundation of the periodic table was put on a more firm bases.
Were it not for the genius of the man that he reserved the place in his table for many elements which were undiscovered yet? Despite the many skeptics, he was proved right again. He was influenced by Bohtlingk, a Sanskrit scholar of Russia who was his friend and was preparing the second edition of his book on the Panini who is known for his grammar of Sanskrit, particularly for his formulation of the 3,959 rules of Sanskrit morphology, syntax and semantics in the grammar known as Ashtadhyayi (अष्टाध्यायी Aṣṭādhyāyī, meaning “eight chapters”), the foundational text of the grammatical branch of the Vedanga, the auxiliary scholarly disciplines of Vedic religion, when he gave the prefixes eka, dvi and tri for unknown elements being 1, 2 and 3 places below known element in the group of elements. For example “ekaboron” was 1 row below and was ultimately identified as Aluminum and so on.
Although the Periodic Table of the Elements was one of the most fruitful ideas to come out of scientific research in the 19th Century, Mendeleev was never awarded a Nobel Prize for this work, although he came within one vote of it in 1906. The reason cited is that one member of the awarding committee argued, rather eloquently, that Mendeleev’s 1869 work had already been widely accepted as a basic part of chemical knowledge, and had already been put forward by the Italian chemist, Stanislao Cannizzaro.
Dmitri Mendeleev died peacefully during a reading of Jules Verne’s Journey to the North Pole, aged 72 on 20 January, 1907. (This was six years after the Nobel Prizes were first awarded).
Since then, 118 elements have been discovered and nearly 30 have been made in the laboratory. Mendeleev has the rare distinction of having an element, that with Atomic Number 101 (Mendelevium), named after him. This synthetic element was obtained by Albert Ghiorso, Glenn T Seaborg and co-workers between 1955 and 1958.