Since iodine is lighter than tellurium, it should be placed immediately down to antimony (Sb = 122). Its position is interchanged with iodine (I = 127). The other thing to notice is the position of tellurium (Te = 128) in the table. This pattern that the elements in the same row have similar characteristics is what we called the periodicity of the elements. These elements have the valency equal to one and shared similar physical and chemical properties. For example, fluorine, chlorine, bromine, and iodine are placed in the same horizontal row. He grouped the elements according to their valency.
Mendeleev's 1869 tableįrom the previous table, the elements were ordered from the top to bottom with increasing atomic weight. The paper was published in the same year in the Russian language, and a German version of the paper consisting of the table and his eight remarks was circulated in Zeitschrift für Chemie. In 1869, his colleague Nikolai Menshutkin on the behalf of Mendeleev presented the paper The Dependence between the Properties of the Atomic Weights of the Elements to the Russian Chemical Society. He formulated his first periodic table by ordering the elements with atomic weights and grouping them based on their valency. He observed that when the elements were arranged in the order of their atomic weights, the properties of elements would regularly repeat over an interval. While working on his book The Principles of Chemistry, he accidentally discovered the periodic law. In the mid-1860s, Mendeleev began writing a book on chemistry. Based on this principle, he not only corrected the properties of known elements but also accurately predicted the properties of undiscovered elements. He explicitly stated the periodic law: The properties of the elements are a periodic function of their atomic weights. Dmitri Mendeleev, a Russian chemist, is widely known for the development of the periodic table and is regarded by the father of the modern periodic table.
0 kommentar(er)
