The periodic table is a tool used in chemistry which lists and ranks elements – gas and solid – by grouping according to weight and atomic number.
Conceptions of science were altered by the development of the periodic table and this is still is a dynamic model today as artificial elements invented in labs are added regularly (for example: curium).
* First steps in the creation of periodic table – The Age of Enlightenment
Initially the French chemist, Lavoisier, published a list of 33 chemical elements in 1789 ranging from gas and metal to earth which was the first attempt to classify elements.
Around twenty years later the German chemist, Dobereiner, grouped these elements into triads according to their chemical properties. This was the first attempt at a formal classification of elements with related properties, for example: lithium, sodium, and potassium were grouped together and recognized as being related due to similar properties or patterns.
Over the next fifty years many chemists contributed to the rapidly expanding body of knowledge on the elements that began to develop: for example Leopold Gmelin, Jean Baptiste Dumas, August Kekule and Julius Meyer.
English chemist John Newlands published a series of papers (1864-1865) that described his attempt at classifying the elements into intervals of eight based on order of increasing atomic weight and similar chemical properties.
*Creation of periodic table – as used today
Russian chemist Dmitri Mendeleev has been credited with the creation and design of the periodic table (1869) as used today although the German chemist, Lothar Meyer produced some similar work at around the same time.
The success achieved by Mendeleev has been attributed to his arrangement of the elements according to their atomic weights which also seemed to be in accord with their valencies and many of their properties. Mendeleev’s predictions that new elements would be discovered, for example eka silicon and eka boron, enabled them to be slotted into the empty spaces he left for them in his periodic table design.
Although Lothar Meyer designed his first periodic table in 1864 it was only based on 28 elements and on valence alone. Neither did Meyer predict the discovery of new elements or recognize where incorrect atomic weights had been allocated to elements. The work of the two chemists listed element in column or row in order of atomic weight and starting a new row or column when the characteristics of the element began to repeat.
Since its creation, there have been refinements to Mendeleev’s periodic table which have involved the inclusion of the noble gases and isotopes.
