The properties of ‘Ekasilicon’ as predicted by Dmitri Mendeleev were confirmed to be the properties of germanium which was discovered in the year 1886, as shown in Table.
His predictions were confirmed correct when these elements such as gallium, scandium and germanium were found later. He made use of the positions of the elements in the Periodic Table to predict the properties of undiscovered elements at that time. Gaps were left in the Periodic Table for undiscovered elements at that time. Elements with similar chemical properties were placed in the same vertical column called a group. In the year 1869, Dmitri Mendeleev, a Russian chemistry professor, arranged the elements in ascending order of their atomic masses as carried out by John Newlands but made a few changes as described below: Lothar Meyer was successful in showing that the properties of the elements were in a periodic pattern with their atomic masses.Ĭontribution by Dmitri Mendeleev (1834 – 1907). Based on these findings, Lothar Meyer compiled a Periodic Table of 56 elements in ascending order of atomic masses based on the periodicity of properties such as atomic volume. Li, Na, K, Rb and Cs (alkali metals) located at the peaks of the curve had similar chemical properties.į, Cl, Br and I (halogens) located at the slopes of the curve also have similar chemical properties. Lothar Meyer realised that elements with similar chemical properties occupied the same relative positions on the curve. The curve obtained by Lothar Meyer is shown in Figure. 
(Definition: Atomic volume of an element is the volume of one mole of atoms of that element.) In the year 1870, Lothar Meyer, a German chemist, plotted a graph of the atomic volume against the atomic mass for all the known elements at that time.
The periodic repetition of the properties of the elements was used as a basis for further development of the Periodic Table.Ĭontribution by Lothar Meyer (1830 – 1895). However, he made an important contribution as he was the first chemist to show the existence of a periodic pattern in the properties of the elements. The classification of elements by John Newlands was not successful because his law of octaves was obeyed by the first 17 elements only (from H to Ca). This arrangement of elements was known as the law of octaves. This pattern was similar to an octave of notes in music. In his arrangement, the same properties were repeated at every eighth element. Each row consisted of seven elements, as shown in Table. From the year 1864 to 1865, John Newlands, a British chemist, arranged all the known elements horizontally in ascending order of their atomic masses. What are Metallic and Nonmetallic Properties?Ĭontribution by John Newlands (1837 – 1898). Periodic Trends in Properties of Elements. How did Mendeleev Arrange the Periodic Table?. Modern Periodic Table and Its Significance. What is the Need for Classification of Elements?. Physical and Chemical Properties of Group 17 Elements. Physical and Chemical Properties of Group 18 Elements. Physical and Chemical Properties of Group 1 Elements. However, the Triad Law had led scientists to realise that there was a relationship between the properties and the atomic masses of the elements. Classification of the elements into triads by Dobereiner was unsuccessful because this classification was limited to a few elements only. Table illustrates two examples of triads. In each triad, the relative atomic mass of the middle element was approximately the average relative atomic mass of the other two elements. Each triad consisted of three elements with similar chemical properties. 
Dobereiner, a German chemist, classified the elements into triads. Light, heat and a few compounds that were unable to decompose into elements such as lime, silica, alumina, barita and magnesia were considered as elements in his table.Ĭontribution by Johann W. The classification by Antoine Lavoisier was unsucessful because his table consisted of many wrong information.Antonie Lavoisier grouped the element into four categories based on their chemical properties: gases, non-metals, metals and earth.
In the year 1789, the known elements at that time were classified into four groups as shown in Table. Antoine Lavoisier, a French chemist, was the first person to classify elements into groups. MoseleyĬontribution by Antoine Lavoisier (1743 – 1794) Dobereiner, John Newlands, Lothar Meyer, Dmitri Mendeleev and H.J.G. The scientists involved in the development of the Periodic Table were:Īntoine Lavoisier, Johann W. What is the history of the periodic table? What is the periodic table of the elements?
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