Tag: background

Periodic Table

September 27, 2018 at 9:18 pmCategory:General

Periodic system of elements (Mendeleev) – classification of chemical elements, allowing them to reveal the dependence of various properties on the atomic mass (more precisely, the number of protons in an atomic nucleus). The system is designed Russian chemist Mendeleev in the years 1869-1871 based on open them in 1869, the periodic law and is its graphic expression. Filed under: NY Museums . Total invited several hundred variants of the image of the periodic system (Analytical curves, tables, geometric figures, etc.). In the modern version of the system is assumed mixing elements in the two-dimensional table in which each column (number of columns is 8) determines the basic physico-chemical properties, and the rows represent the periods, to some extent similar to each other. The original work was titled Mendeleev as "Experience of elements based on their atomic weight and chemical similarity. According to legend, the idea of such a system came to him in a dream, but we know that once asked how he discovered the periodic system, Mendeleev said: "I'm over it, maybe twenty years of thought, and you think: sitting and suddenly Done. Click NY Museums to learn more.

German L. Meyer in 1864 on the basis of data on atomic weights suggested a table showing the ratio of atomic weights for several characteristic groups of elements. Many, especially in Germany, and believe it discoverer of the system – in 1870 he published his table of elements, developed, apparently independently of Mendeleev. Not to be confused with copyright, most students of the Western world are studying this system simply as "periodic system of elements", without mentioning the name of the discoverer. The essence of the discovery is that with increasing atomic weight of the chemical element of its properties do not change monotonically, but periodically. After a certain number of different properties of elements arranged in increasing atomic weight, the properties begin to repeat.

For example, sodium, like potassium, neon like argon, while gold is similar to silver and copper. Of course, the properties are not repeated exactly, are added to them and change. Subsequently, it became clear that the periodicity of the system elements is determined not by atomic weight, and the nuclear charge or atomic number of which depends on the structure and the filling of electronic shells of an atom of the element (atomic orbitals). Periodic system of elements

James Works

January 11, 2017 at 7:03 amCategory:General

Sometimes the origin of the letter is not mention of one of the letters also say this: 'letter to these things found a boy of seven orphan who before did not say' (17). This motif is present today in most modern 'letters': it says that it (Letter) finds seven (rarely – twelve) boy, who was sick and had recovered after rewriting pisma.I letter itself was reduced in a modern edition to intonation (the prayer-treatment). Rewriting the 'Holy Letter ', in ancient Rus people like praying, praising God, and so, perhaps, consciously or not – to ease their dushu.Eto likely, because in ancient cultures' literature – svyaschennodeystvie.Chitatel was in some respect and was coming .On works as an icon with a sense of awe .Ottenok maintained even when the work was a secular '(18). These words, of course, can not be distributed to modernity, but they may be, to some extent valid in relation to the scribes 'Holy Letters'. Read additional details here: Bill de Blasio. The task of the messages were specific. Accustom to celebrate Sunday – that is, to observe the Christian tradition, often violated, and cure him of some habits, occupation, counted the legacy of paganism (19). The same role played by the works of Russian moralistic literature emanating from the pastors of the church: 'The word on the afternoon of blissful Eusebius Archbishop ',' Holy Father's words of Jacob on the holy days of the week '.' The word of the week, James, the brother of the Lord, Bishop of Jerusalem 'and others. In XV-XVI centuries 'zealots of piety' wrote and distributed their with the same goal by works' in the spirit of Nomocanon and based on his .