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Mendeleev then used his table to predict the existence of elements that would have the properties similar to Aluminum and silicon but still remained undiscovered. He placed elements with similar properties in vertical groups and left gaps in the table for those that were yet to be identified and for those elements which did not seem to follow the same trend as other elements. Dimitri Mendeleevĭmitri Mendeleev in 1869 and Lothar Meyer in 1870 also recognized that there was a periodic relationship among the properties of the elements. His attempts to force the other elements to obey this same pattern which he called “the law of octaves” failed miserably and so his theory was not accepted by other chemists of the time. This, however, only worked for the first 17 elements. He observed that the properties of elements appeared to repeat themselves every eighth element and so grouped them accordingly. John Newlands, was one of the first to arrange the elements into a table using the order of increasing atomic weight in 1864. The periodic table has been rearranged by many chemists over time with the aim of showing the relationship between different elements. The non-metals, fluorine (F), chlorine (Cl), bromine (Br), and iodine (I) also exhibited similar properties to each other, but these properties were drastically different from those of any of the elements above. However, when the properties of the two groups were compared they were notably different from each other. The metals calcium (Ca), strontium (Sr), and barium (Ba), were also shiny, good conductors of heat and electricity, and had other similar properties.

In doing this, they realized that certain elements showed similarities in their properties and were, therefore, able to be grouped together.įor example lithium (Li), sodium (Na), and potassium (K) were all shiny, conducted heat and electricity well, and reacted violently in water. Many of the elements from the periodic table we know today were originally discovered by the early chemists who worked to purify ores.

The History of the Periodic Table of Elements