Mendeleev contribution laid the foundation of modern periodic table.
Answers
yes its true....
MARK AS BRAINLIEST
Answer:
father of periodic table
Explanation:
1863, there were 56 known elements with a new element being discovered at a rate of approximately one per year. Other scientists had previously identified periodicity of elements. John Newlands described a Law of Octaves, noting their periodicity according to relative atomic weight in 1864, publishing it in 1865. His proposal identified the potential for new elements such as germanium. The concept was criticized and his innovation was not recognized by the Society of Chemists until 1887. Another person to propose a periodic table was Lothar Meyer, who published a paper in 1864 describing 28 elements classified by their valence, but with no predictions of new elements.
After becoming a teacher in 1867, Mendeleev wrote the definitive textbook of his time: Principles of Chemistry (two volumes, 1868–1870). It was written as he was preparing a textbook for his course.[25] This is when he made his most important discovery.[25] As he attempted to classify the elements according to their chemical properties, he noticed patterns that led him to postulate his periodic table; he claimed to have envisioned the complete arrangement of the elements in a dream:[27][28][29][30][31]
I saw in a dream a table where all elements fell into place as required. Awakening, I immediately wrote it down on a piece of paper, only in one place did a correction later seem necessary.
Unaware of the earlier work on periodic tables going on in the 1860s, he made the following table:
Cl 35.5 K 39 Ca 40
Br 80 Rb 85 Sr 88
I 127 Cs 133 Ba 137
By adding additional elements following this pattern, Mendeleev developed his extended version of the periodic table.[34][35] On 6 March 1869, he made a formal presentation to the Russian Chemical Society, titled The Dependence between the Properties of the Atomic Weights of the Elements, which described elements according to both atomic weight (now called relative atomic mass) and valence.[36][37] This presentation stated that
The elements, if arranged according to their atomic weight, exhibit an apparent periodicity of properties.
Elements which are similar regarding their chemical properties either have similar atomic weights (e.g., Pt, Ir, Os) or have their atomic weights increasing regularly (e.g., K, Rb, Cs).
The arrangement of the elements in groups of elements in the order of their atomic weights corresponds to their so-called valencies, as well as, to some extent, to their distinctive chemical properties; as is apparent among other series in that of Li, Be, B, C, N, O, and F.
The elements which are the most widely diffused have small atomic weights.
The magnitude of the atomic weight determines the character of the element, just as the magnitude of the molecule determines the character of a compound body.
We must expect the discovery of many yet unknown elements – for example, two elements, analogous to aluminium and silicon, whose atomic weights would be between 65 and 75.
The atomic weight of an element may sometimes be amended by a knowledge of those of its contiguous elements. Thus the atomic weight of tellurium must lie between 123 and 126, and cannot be 128. (Tellurium's atomic weight is 127.6, and Mendeleev was incorrect in his assumption that atomic weight must increase with position within a period.)
Certain characteristic properties of elements can be foretold from their atomic weights.
Mendeleev published his periodic table of all known elements and predicted several new elements to complete the table in a Russian-language journal. Only a few months after, Meyer published a virtually identical table in a German-language journal.[38][39] Mendeleev has the distinction of accurately predicting the qualities of what he called ekasilicon, ekaaluminium and ekaboron (germanium, gallium and scandium, respectively).
For his predicted eight elements, he used the prefixes of eka, dvi, and tri (Sanskrit one, two, three) in their naming. Mendeleev questioned some of the currently accepted atomic weights (they could be measured only with a relatively low accuracy at that time), pointing out that they did not correspond to those suggested by his Periodic Law. He noted that tellurium has a higher atomic weight than iodine, but he placed them in the right order, incorrectly predicting that the accepted atomic weights at the time were at fault.
By using Sanskrit prefixes to name "missing" elements, Mendeleev may have recorded his debt to the Sanskrit grammarians of ancient India, who had created sophisticated theories of language based on their discovery of the two-dimensional patterns of speech sounds (arguably most strikingly exemplified by the Śivasūtras in Pāṇini's Sanskrit grammar). Mendeleev was a friend and colleague of the Sanskritist Otto von Böhtlingk, who was preparing the second edition of his book on Pāṇini[41] at about this time, and Mendeleev wished to honor Pāṇini with his nomenclatur..