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Read and translate the list of chemical elements with their symbols and atomic number: (in alphabetical order)

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II. Translate the following sentences:

 

In chemical industry (the one which produces acids, bases and salts) sulphuric acid is used for the preparation of practically important sulphates, such as copper sulphate, ferrous sulphate, amrnonium sulphate and etc.

Being a strong and nonvolatile acid, sulphuric acid is used for the production of weaker and more volatile other acids from their salts.

Large quantities of sulphuric acid are used for the production of mineral fertilizers: ammonium sulphate, superphosphate, etc.

Most of me rare metals, pure or alloyed, have a great number of valuable physical and chemical properties.

Germanium, indium, tellurium, selenium, etc. are used in the production of semi­conductors (i.e. substances which have different electrical resistances in two opposite directions).

To produce alloys resistant to high temperature, which are needed in design of jet and rocket motors, nickel, chromium, cobalt, titanium and molybdenum are used. Metal cutting tools are made of hard alloys of chromium, tungsten, titanium, etc.

 

III. Translate into Russian:

The atomic number indicates the number of protons within the core of an atom. The atomic number is an important concept of chemistry and quantum mechan­ics. An element and its place within the periodic table are derived from this concept When an atom is generally electrically neutral, the atomic number will equal the number of electrons in me atom, which can be found around the core. These electrons mainly determine the chemical behaviour of an atom. Atoms that carry electric charges are called ions. Ions either have a number of electrons larger (negatively charged) or small­er (positively charged) than the atomic number.

 

Atomic mass

The name indicates the atomic mass of an atom, expressed in atomic units of mass (u). Each isotope of a chemical element can vary in mass. The atomic mass of an iso­tope indicates the number of neutrons that are present within the core of the atoms. The atomic mass indicates the number of particles within the core of an atom; this means the protons and neutrons. The total atomic mass of an element is an equivalent of the mass units of its isotopes. The relative occurrence of the isotopes in nature is an important factor in the determination of the overall atomic mass of an element.

Densit y

The density of an element indicates the number of units of mass of the element that are present in a certain volume of a medium. Traditionally, density is expressed through the Greek letter ro (written as p). Within the SI system of units density is expressed in kilograms per cubic meter (kg/m3). The density of an element is usually expressed graphically with temperatures and air pressures, because these two properties influence density.

 

IV. Translate into English:

 

а) Плотность характеризует массу соединения. Химики постоянно использу­ют величину, называемую относительной плотностью, которая является отноше­нием массы неизвестного вещества и хорошо известного, например воды.

Относительная плотность вещества - это масса некоторого объема этого ве­щества, деленного на массу того же объема воды.

б) Явление, при которых происходит превращение одних веществ в другие, т.е. изменения состава вещества, называется химическими явлениями, или хими­ческими реакциями.

в) Молекулярным весом вещества называется вес его молекулы, выраженной в кислородных единицах. Молекулярный вес показывает, во сколько раз молекула вещества тяжелее 1/16 веса атома кислорода.

г) Вес вещества, вступившего в реакцию, равен весу веществ, образовавших­ся в результате реакции. Каждое сложное вещество имеет постоянный качествен­ный и количественный состав независимо от способов его получения.

д) Атом - наименьшая часть химического элемента, являющегося носителем его свойств. Атом состоит из атомного ядра и электронной оболочки, в которой на определенных уровнях располагаются электроны. Общее количество электронов равно порядковому номеру в периодической таблице Д.М. Менделеева.

 

V. Translate the following information into English:

 

В основе системы лежит закон периодичности: «Свойства химических эле­ментов находятся в периодической зависимости от заряда их атомных ядер» Заряд ядра равен атомному номеру элемента в системе. Элементы, расположенные по возрастанию заряда ядра, образуют 7 периодов. В периодах свойства элементов закономерно изменяются при переходе от щелочных металлов к благородным газам. Химические и физические свойства элементов определяют их положение (место) в периодической системе. Тяжёлые ядра неустойчивы, например, амери­ций (заряд ядра 95) и последующие элементы в периодической системе не обнару­жены в природе. Их получают искусственно в ходе ядерных реакций.

В январе 2004 года был успешно завершен эксперимент российских ученных по синтезу нового элемента. Синтез 115-го и 113-го элементов периодической сис­темы был зарегистрирован в институте ядерных исследований в Дубне. В экспери­менте принимали участие американские специалисты из калифорнийской нацио­нальной лаборатории ядерных исследований. В результате этого открытия общее количество химических элементов в периодической системе увеличилось до 116.

 

 

LESSON #2

ANATOMY OF THE ATOM

 

A very simplistic visualization of an atom includes a dense nucleus comprised of a specific number of positively charged protons and uncharged neutrons surrounded by orbits of negatively charged electrons.

 

One might be tempted to envision a configuration similar to a solar system with the nucleus representing the sun and the electrons representing planets. While this is a good starting point, you will soon discover that the solar system model does not provide a true representation of the atom.

 

Atomic Number

The number of protons always equals the number of electrons in an atom, and that number is equal to the atomic number. For instance, carbon has an atomic number of six and therefore has six protons and six electrons.

 

Atomic Mass

The weight of an atom is determined by the number of neutrons and protons that are present in the nucleus. The proton and neutron, which are similar in mass, each weighs approximately 1,836 times greater than a single electron, thus the mass contributed by electrons is insignificant when determining atomic weight or atomic mass. The atomic mass is the sum of the protons and neutrons in the nucleus. Carbon has an atomic mass of twelve. Since there are six protons in carbon (remember, it has an atomic number of six and, therefore, must have six protons), it must have six neutrons:

Atomic Mass = # Protons + # Neutron

The atomic mass of carbon = 12

The atomic # of carbon = 6 = the # of protons

# neutrons = Atomic Mass - # protons

# neutrons =12 -6 = 6

The Variability in the Number of Neutrons in Each Element (Nuclides / Isotopes) While the number of protons and electrons remain constant in the neutral atom, the number of neutrons may vary within different atom species of the same element. As a result, the atomic mass for one atom may be different from another atom of the same element if the number of neutrons varies. Atomic mass must account for all possible species or nuclides (isotopes), of an atom. Carbon 12 with its 6 neutrons is by far the most common isotope of carbon. In reality, there is a carbon 14 which has eight neutrons and an atomic mass of 14. There is also a carbon 11 which has only five neutrons.

 

The Atomic Mass Average

This is the sum of all nuclide (isotope), masses multiplied by their natural abun­dance. This weighted average is the relative mass listed in the Periodic Table. The relative percentage of each nuclide (isotope), appears to be similar throughout the world:

 

The Charge of an Atom

Since the number of protons (positive charges) always equals the number of elec­trons (negative charges) in an atom, positive charges equal negative charges and atoms in the elemental state have no charge. Only when an atom takes an electron from another atom does the particle become charged. This charged form of the atom is known as an ion. Positively charged ions are called cations, and negatively charged ions are called anions. For instance, when chlorine accepts an electron from sodium, the sodium ion that is formed will have one more proton than electrons. It will therefore have a positive charge and be called a cation. The chlorine (or chloride) ion will have one more electron than protons. It will take on a negative charge and be called an anion. The compound formed by this transfer of electrons is sodium chloride or table salt, which is nothing like the highly reactive sodium or extremely poisonous chlorine from which it was formed.

 

Energy Levels

Until now we have focused on the nucleus. Lets turn our attention to the electrons, which surround the nucleus of the atom. Electrons are located in energy levels a term which has replaced the word shells, which was once used to describe the location of electrons. The word shell suggests a fixed position, which is far from reality. We will use energy level to describe the possible location of electrons.

There are seven energy levels. Each has a specific maximum number of electrons that can exist in it. The number of electrons, which an energy level can hold is equal to 2nl where n = energy level. The letter n represents the principal quantum number that specifies the energy level of the atom in which an electron is located. The chart below identifies the various energy levels and maximum number of electrons possible. The energy level closest to the nucleus is represented by energy level 1.

 

Electron Energy Levels

 

 

Energy Sublevels (Orbitals) Within each principal energy level is one or more energy sub levels (Orbitals) or subshells. The number of sublevels possible for any one principal energy level is equal to the value of the quantum number (n) for that energy level. While there are theoretically 7 possible sublevels, only four are actually used for the known elements. The others are not currently needed. Sublevels are numbered with consecutive whole numbers. The first sublevel is 0 followed by numbers 1 through 6. These numbers are the azimuth at quantum number s. The value of can never be greater than n.

 

WORDLIST:

 

Nuclide (isotope) - изотоп

Abundance - количество; численность

percentage - содержание, соотношение

cations - катионы, положительно заряженные ионы

anions -анионы, отрицательно заряженные ионы

shell - оболочка

energy level - энергетический уровень

quantum number - квантовое число

subshell -подоболочка

opaque - непрозрачный, светонепроницаемый

 

EXERCISES:

I. Put 6 questions to the text and answer them:

a) What is the general configuration of an atom?

 

II. Translate the following sentences in to Russian:

 

Liquids are characterized by possessing a definite volume but no fixed form; they take the shape of the vessel containing them, except when in minute quantities, as drops, they assume a form more or less spherical. According to the kinetic theory, the mol­ecules of a liquid are packed close together and attract one another; the attraction is not great enough, however, to prevent their motion. There is not much free space between the molecules, because liquids are very incompressible - a great pressure has little effect in decreasing the volume of a liquid.

Solids possess a definite form. According to the kinetic theory the molecules are closely packed, and the attraction between them is great enough to prevent free motion, ft is possible in a solid, therefore, to have a definite arrangement of the molecules which remains fixed; this is seen in the fact that many solids assume definite forms which are characteristic. For example, when sodium chloride separates from a solution in water, it appears as cubes. Other substances appear in other geometric forms.

Substances which are composed of identical molecules are pure substances (pure water, pure oxygen and etc.). Substances which are composed of the molecules of dif­ferent pure substances are mixtures and compound substances.

By the atomic-molecular theory, chemical reactions represent a rearrangement of atoms into new molecules. This rearrangement is accompanied by the liberation of heat, gas, radiation or by the absorption, for entrance, the same heat.

The rate of chemical reaction is measured by the change in the concentration of one of the substances or of one of the products, per unit of time. The most important factors which influence the rate of chemical reactions are: the concentration of the substance, the temperature and the presence of a catalyst.

 

III. Translate the following text and be ready to discuses properties of elements:


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