Dobereiner s triads biography for kids

Johann Wolfgang Döbereiner (13 December – 24 March ) was a German chemist who is best known for work that foreshadowed the periodic law for the chemical elements, and for inventing the first lighter, which was known as the Döbereiner's lamp. He became a professor of chemistry and pharmacy at the University of Jena.

Life and work

As a coachman's son, Döbereiner had little opportunity for formal schooling. Thus, he was apprenticed to an apothecary, and began to read widely and to attend science lectures. He eventually became a professor at the University of Jena in and also studied chemistry at Strasbourg. In work published in , Döbereiner reported trends in certain properties of selected groups of elements. For example, the average of the atomic masses of lithium and potassium was close to the atomic mass of sodium. A similar pattern was found with calcium, strontium, and barium; with sulfur, selenium, tellurium; and with chlorine, bromi

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Dobereiners Triads &#; Definition, Types, Limitations

Since ancient times, there have been various attempts to classify the elements into groups according to their properties. As the new elements were discovered, a number of theories came up to classify the elements. Various scientists used various approaches and facts to justify their classification. These theories were refined more and more and finally lead to the development of the modern periodic table. Let us have a look at one of these old theories i.e. Dobereiner’s triads.

Dobereiner’s triads

A German chemist Johann Wolfgang Dobereiner identified that elements with similar properties could be grouped together in groups of three which were referred to as triads. The elements in a particular triad had similar kemikalie and physical properties. 

Law of Triads: According to Dobereiner, when elements are arranged in increasing order of their atomic masses, the arithmetic mean of the atomic masses of the first and third

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Dobereiner's Periodic Table

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D�bereiner, Johann Wolfgang (Germany, )

 During the s D�bereiner�s experiments with the ignition of hydrogen on contact with powdered platinum led the Swedish chemist J.J. Berzelius to develop the concept of catalysis. Toward the end of the decade D�bereiner found that the properties of bromine, a liquid, seem halfway between those of chlorine gas and the solid iodine. He recalled a comparable graduation of properties in two other sequences, i.e. calcium, strontium, barium; and sulfur, selenium, tellurium. Each of Dobereiner's triads was a group of three elements. The appearance and reactions of the elements in a triad were similar to each other. He showed that in each triad the mean of the lightest and heaviest atomic weights approximated the atomic weight of the middle element. But he could not substantiate his hypothesis with a sufficient number of triads, and his findings were regarded in his time as me