Elements of the System

2018 ◽  
pp. 11-43
Keyword(s):  
Inorganic Chemistry ◽  
Periodic System ◽  
Educational Institutions ◽  
Scientific Career ◽  
Basic Principles ◽  
Law Of Nature ◽  
Chemistry Textbook ◽  
System P ◽  
Periodic Law

This chapter examines Dmitrii Mendeleev's formulation of the periodic system. The periodic system was the product of twin pedagogical trajectories: Mendeleev's personal trajectory through the educational institutions of St. Petersburg in his attempt to solidify a scientific career and an effort to introduce the totality of chemistry through a set of easily understood basic principles. Consequently, the periodic law emerged out of the periodic system of elements, the tabular classification that Mendeleev composed in early 1869 at St. Petersburg University. He created the periodic system to address a specific set of demands that arose in the composition of a new inorganic chemistry textbook—pedagogical problems of classification and organization. How the classification of elements became a periodic system and then a law of nature was intimately tied with how Mendeleev became increasingly secure at St. Petersburg University.

From Simple Substance to Chemical Element

2020 ◽  
pp. 32-52
Author(s):  
Bernadette Bensaude-Vincent
Keyword(s):  
Periodic System ◽  
Chemical Element ◽  
Traditional View ◽  
Modern Concept ◽  
Simple Substance ◽  
System P ◽  
Conceptual Distinction ◽  
Definition Of

The introduction of the modern concept of chemical element has often been credited to Lavoisier. I will argue that despite the significant impact of the definition of elements as non-decompound bodies in Lavoisier’s “Elements of Chemistry,” this claim is misleading for at least three reasons. First, elements were already defined as residues of analysis prior to Lavoisier. Second, Lavoisier did not totally give up the traditional view of elements as constituents of all bodies. Third, the modern definition of chemical element implies a clear distinction between simple bodies and elements that was later introduced by Dmitri Mendeleev. I will outline the role of this conceptual distinction in Mendeleev’s process of classification of elements and symmetrically emphasize how the periodic system contributed to stabilize his notion of element as an individual defined by its position in the system. Thus the concept of element appears as both a precondition and a product of the construction of the periodic system.

From Dalton to the Discovery of the Periodic System

2013 ◽  
Author(s):  
Eric Scerri
Keyword(s):  
Periodic System ◽  
Quantitative Data ◽  
Quantitative Characteristic ◽  
Good Deal ◽  
Ancient Greek ◽  
System P ◽  
Quantitative Property ◽  
To Come ◽  
First Time

Our story begins, somewhat arbitrarily, in the English city of Manchester around the turn of the nineteenth century. There, a child prodigy by the name of John Dalton, at the tender age of fifteen is teaching in a school with his older brother. Within a few years, John Dalton’s interests have developed to encompass meteorology, physics, and chemistry. Among the questions that puzzle him is why the various component gases in the air such as oxygen, nitrogen, and carbon dioxide do not separate from each other. Why does the mixture of gases in the air remain as a homogeneous mixture? As a result of pursuing this question, Dalton develops what is to become modern atomic theory. The ultimate constituents of all substances, he supposes, are hard microscopic spheres or atoms that were first discussed by the ancient Greek philosophers and taken up again by modern scientists like Newton, Gassendi, and Boscovich. But Dalton goes a good deal further than all of these thinkers in establishing one all-important quantitative characteristic for each kind of atom, namely its weight. This he does by considering quantitative data on chemical experiments. For example, he finds that the ratio for the weight in which hydrogen and oxygen combine together is one to eight. Dalton assumes that water consists of one atom of each of these two elements. He takes a hydrogen atom to have a weight of 1 unit and therefore reasons that oxygen must have a weight of 8 units. Similarly, he deduces the weights for a number of other atoms and even molecules as we now call them. For the first time the elements acquire a quantitative property, by means of which they may be compared. This feature will eventually lead to an accurate classification of all the elements in the form of the periodic system, but this is yet to come. Before that can happen the notion of atoms provokes tremendous debates and disagreements among the experts of Dalton’s day.

Basic principles for classification of equipment of energy facilities

2020 ◽  
Vol 13 (1) ◽  
pp. 4-10
Author(s):  
E. P. Grabchak ◽  
A. I. Vorobyev ◽  
S. V. Mischeryakov
Keyword(s):  
Basic Principles

THE IMPORTANCE OF THE LAW "ON OPERATIONAL INSPECTION ACTIVITIES" IN THE IMPLEMENTATION OF PREVENTION OF OFFENSES

2021 ◽  
Vol 6 (6) ◽  
pp. 71-78
Author(s):  
Farxod Djurayev ◽  
Keyword(s):  
Legal Status ◽  
Legal Protection ◽  
Law Enforcement Officers ◽  
Joint Work ◽  
Basic Principles ◽  
The Law ◽  
Causes Of Crime ◽  
Prevention Of Crime

The article is devoted to the prevention of crime, maintenance of public order and early crime prevention, identification and elimination of the causes of crime in each district, family and individual, classification of each district depending on the crime situation in these regions and joint work to attract all forces and means to identify and eliminate the causes of crime, the role of the law "On operational-search activities" in the prevention of offenses, the concept of operational-search activities, the main tasks, basic principles; bodies carrying out operational-search activities, their legal status; types of operational-search measures and their comments regarding the procedure for conducting a search; social and legal protection of law enforcement officers and persons assisting in the conduct of such events, as well as their family members

scholarly journals Key Navigation-Ballistic Technologies for Improving the Efficiency of Spacecraft Control

2021 ◽  
Vol 8 (3) ◽  
pp. 3-10
Author(s):  
А. E. Tyulin ◽  
◽  
V. V. Betanov ◽  
Keyword(s):  
Basic Principles ◽  
Spacecraft Control ◽  
General Classification ◽  
Early Stages ◽  
Technological Cycle ◽  
Efficient Control ◽  
Different Types ◽  
Processing Algorithms

The article focuses on the issues of creating promising space technologies, their general characteristics, and special features. The basic principles for creating and implementing key navigation-ballistic technologies, which help ensure efficient control of spacecraft, are substantiated. A classification of the technologies is proposed based on the characteristics most often used in the area under consideration. Two bar charts of a typical technological cycle of navigation-ballistic support with the possibility of processing a joint sample of measurements of current navigation parameters and recurrent Kalman processing algorithms are analyzed. A variant of a general classification of technologies that allows singling out and correlating different types and classes of technologies is given. This contributes (especially at the early stages) to the improvement of the efficiency of their development.

Technical means of customs control and their classification

2021 ◽  
pp. 53-62
Author(s):  
Minnegaley Gizyatovich Akhmetov
Keyword(s):  
Educational Process ◽  
Educational Institutions ◽  
Practical Application ◽  
Higher Educational Institutions ◽  
Field Of Study ◽  
Higher Educational

The article discusses the classification of technical means of customs control. The modern views on the field of application of technical means of customs control when passing goods and vehicles through the customs border of the Eurasian Union are disclosed. The approaches to grouping, classification of technical means of customs control are clarified. The data in the article can be used by customs authorities in organizing the practical application of technical means of customs control and in the educational process of higher educational institutions in the «Customs» field of study.

The Periodic System

2019 ◽  
Author(s):  
Eric Scerri
Keyword(s):  
Middle Ages ◽  
Point Of View ◽  
Platonic Solid ◽  
Ancient Greek ◽  
Platonic Solids ◽  
System P ◽  
Chemical Inertness ◽  
Dimensional Shape ◽  
The Many

In ancient Greek times, philosophers recognized just four elements—earth, water, air, and fire—all of which survive in the astrological classification of the 12 signs of the zodiac. At least some of these philosophers believed that these different elements consisted of microscopic components with differing shapes and that this explained the various properties of the elements. These shapes or structures were believed to be in the form of Platonic solids (figure 1.1) made up entirely of the same two-dimensional shape. The Greeks believed that earth consisted of microscopic cubic particles, which explained why it was difficult to move earth. Meanwhile, the liquidity of water was explained by an appeal to the smoother shape possessed by the icosahedron, while fire was said to be painful to the touch because it consisted of the sharp particles in the form of tetrahedra. Air was thought to consist of octahedra since that was the only remaining Platonic solid. A little later, a fifth Platonic solid, the dodecahedron, was discovered, and this led to the proposal that there might be a fifth element or “quintessence,” which also became known as ether. Although the notion that elements are made up of Platonic solids is regarded as incorrect from a modern point of view, it is the origin of the very fruitful notion that macroscopic properties of substances are governed by the structures of the microscopic components of which they are comprised. These “elements” survived well into the Middle Ages and beyond, augmented with a few others discovered by the alchemists, the precursors of modern-day chemists. One of the many goals of the alchemists seems to have been the transmutation of elements. Not surprisingly, perhaps, the particular transmutation that most enticed them was the attempt to change the base metal lead into the noble metal gold, whose unusual color, rarity, and chemical inertness have made it one of the most treasured substances since the dawn of civilization.

Tumors of the Central Nervous System

2013 ◽  
pp. 20-58
Author(s):  
Keith L. Ligon ◽  
Karima Mokhtari ◽  
Thomas W. Smith
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Molecular Biology ◽  
Tumor Type ◽  
Primary Tumors ◽  
System P ◽  
Precise Diagnosis ◽  
The Central Nervous System ◽  
Classification Of Tumors

This chapter presents the most up-to-date classification of tumors of the nervous system, based on the histological appearance of the neoplasm and also on information derived from cytogenetics and molecular biology, now recognized worldwide as increasingly important for more precise diagnosis, prognosis, and therapeutic guidance. The chapter provides a detailed morphologic description of each major tumor type, with numerous illustrations of macroscopic and microscopic lesions. First we consider primary tumors of the nervous system, including those derived from neuroepithelial tissue (astrocytic, oligodendroglial, ependymal, neuronal, and glioneuronal), pineal tissue, peripheral nerve sheath, and meninges. Next lymphomas, hematopoietic neoplasms, and secondary (metastatic) neoplasms are described.

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