Periodic Table History

Johann Wolfgang Dobereiner

1829

German scientist. In 1828 found groups of 3 elements that showed similar properties, this groups were called Dobereiner's triads. He could only identify some triads of the elements, the others didn't obey the rule, it wasent usefull at all.

Newlands

1863

British chemist. By this time 56 elements were discovered. He order all the elements in a increasing order of their atomic masses. He found out that every eight element had similar properties to the first. This clasification was known as the Newlands Octaves. He could only organise this elements up to calsium, then other elements did not fit in as well

Dmitri Ivanochive Mendeleev

1869

Russan chemist. He belived that the atomic masses of the elements was the most important property in classifing the elements. He organised the elements in the increased order of their atomic masses and properties. He created the first periodic table containing 63 elements known as Mendeleev periodic table. It had some irregularities in the positions of the elements so they discarded it.

Henry Moseley

1913

English physicist. He discovered that atomic number is the most fundamental property of an element and not its atomic mass. The modern periodic law was created: "The chemical or physical properties of elements are a periodic function of their atomic number". He created the Modern Periodic Table.