Sunday, August 16, 2009

The Idea of The Atom

Further information about the idea of the atom.

Models and mechanisms of particle behavior, and other materials have been for thousands of years. Especially in the past centuries, but these models have been improved and clarified. In the following chapters some of these events are, as the path of our current model of the atom, which explains all the laws and that their behavior.

The first model of the type of atoms and it was in ancient times. Leukippos Greek philosopher (ca. 500-400 BC) and his pupil Democritus (ca. 460-370 BC) were the first to describe this issue in our world as a collection of atoms (in Greek: indivisible). His theory is based on the idea that if a body into smaller parts to a certain point are so small that they can no longer divide. You have the words to describe this issue are made. According to this theory, the atoms are small organizations that are not shared.

Atoms are made of various materials in different composition and size. The properties of the materials, and is therefore due to differences of the individual atoms: the differences in their size, their grouping and mutual understanding. Beginning of the 19th Century, the model of atomic mass on which Greek and after J. Dalton (1766-1844). According to his theory, which is made up of small particles called atoms

The atoms of all materials used are distinguished by their weight and their size. In the course of chemical reactions, the atoms remain unchanged. Of course, the number and position of atoms in the reagents and the compounds can not change. Be combined in the region that the change in the proportions and combinations in a single reaction. In much the atomic mass atoms consist of a nucleus and electrons.

The atom is, of course, from elementary particles. At the center of an atom of neutrons (free) and positively charged protons. Atoms of the same element always contains the same number of protons. Only the number of neutrons can vary slightly (in the isotopes). The atoms of the same element that differ only by the number of neutrons they contain, and its atomic mass. Otherwise, the isotopes of an element have the same physical and technical characteristics and the element itself

The core is on average relatively small compared to the atom itself, the bulk of the mass of an atom. The mass of protons and neutrons, the number 1. The number of protons in an atom determines its atomic number. This number is also the symbol of the atom, or an element of the periodic table of elements. (Hydrogen (H) = 1, helium (He) = 2, etc.). The electrons (negatively charged particles) around the nucleus of an atom electronic orbital resources, where you can find. Its mass is relatively small - 1 / 1836 of the mass of protons and neutrons. There are so many electrons that the number of protons in the nucleus. Therefore, every atom in its natural state is neutral.

Atoms can lose one or more of its electrons. If they do, they are positively charged. Furthermore, atoms can gain electrons, the negatively loaded. When an atom gains or loses electrons is the ion. Outside the scope of an atom, the shell, out of mind, and where are the electrons, making the most of his size. This area is primarily a gap. The electrons move in certain areas around the nucleus. Some electrons are closer to the core, the other (within the orbit, the electrons or closed). Others are farther from the core (the outermost layer of electrons).

Nucleus of an atom does not change during a chemical reaction. For this reason, it is very important. Of course, the electrons of an atom determine the behavior of the skin (in most cases, the electrons in the rail).

The energy of an electron is defined by means of letters and numbers, depending on the train where the electron. Of great importance is the removal of an electron by the core. The exact location of the electrons of an atom, it is impossible to determine because of the situation and the email address of a person can not be calculated (Heisenberg uncertainty principle).

More precisely, we seek to the position of an electron, less precise, our ability to determine its direction. Why? Since it is impossible to tell in which direction the electrons move in the time they have established their position. Unfortunately, only the probability that the electron can be calculated. Even if we know that the Executive an electron is moving, its exact location can not be localized. The course, simply the area where a particular electron energy can be found, it is more likely is Erdumkreisung atomic radius.

Duality

Because of their atoms and electrons can not be studied directly, the reality on the atomic level is more or less unknown. Atomic radius features which can be seen, however, the atomic models can be. The accuracy of the models is in their ability to explain certain phenomena. Often these very small particles have characteristics that are not often used in the macro world we live in are capable of the electrons of a certain principle of duality - such as the light: the duality of waves and particles. This means that on the one hand, an electron can be a kind of particle beam, like a rifle with radiation. In addition, the electrons of a pure wave-like. The electrons are not, however, one or the other, because these two features are contradictory. But both approaches need to be able to describe the behavior of an electron. Wave mechanical model of the description of the atomic structure of a foreign atom and the nature of the waves, like electrons.

Numbers quantum effects

In the model atom Niels Bohr (Danish physicist), a swarm of swarms of electrons around the nucleus of an atom. The electrons are in circulation, that in certain orbits around the nucleus. The orbit represented a certain amount of energy. All the electrons in orbit than the same amount of energy.

The energy of an electron has a quantum yield n. The largest number, the more energy an electron, which is far away from the nucleus.

When an excited electron is orbiting the furthest from the core, one with a higher energy, energy, and must therefore be on the electrons (a quantum). When an electron moves to a higher energy orbit to a lower energy orbit, closer to the core, the energy must not be in the form of radiation (heat, light or other type of 'electromagnetic energy. With the help of the principal quantum number is to calculate the maximum number of electrons on the outside of an atom.

The number of electrons in an atom can be calculated using the following formula 2N2, where n is the principal quantum number. Atomic radius quantum numbers to describe an atom and the electrons. A second number of quantum mechanics, as L, is the return of an electron, or its angular design time. This means that the spatial geometry. This is of crucial importance to the determination of chemical bonds in the atoms, there is a.

The energy of an electron is essentially defined by the principal quantum number n and to a lesser extent by the second quantum number l. The position of the energy, an electron from its orbit (in which the electron moves) over the outside of the magnetic field, the magnetic quantum m (many quantum-address) can be determined. After the value of m, Orbit resources can be a function of their energy.

There is a Erdumkreisung s (spherically symmetrical around the nucleus), three p orbital resources (which is probably dumbbells three decks in the core and its pointing in three directions), five d orbital resources (four-leaf structures between the p orbital resources) and seven f Orbit Resources Within each type (s, p, d, f) are the same orbital energy. If we take the electron as a small, one can imagine that its axis turns, left or right. Direction of rotation is in turn is determined by the quantum number s, for the company. With the help of these four numbers quantum effects, each electron can be precisely described.

DC electron orbital

The transfer of electrons from their orbits of the electrons is configuration. According to the principle of Pauli (Swiss-American physicist), no more than two electrons in orbit at any given time.

Orbital resources are provided by the low energy electrons with higher energy Erdumkreisung train (in the order s, p, d, f). Firstly, all orbital resources of a specific energy of an electron. Then compared to the orbit of the rotation moves on a rail of the first electron. After two electrons in an orbital is completely full. The two electrons of a pair of electrons. Single odd electrons are electrons. In each of the main elements of the group, all orbital resources SYP gradually met, such as electrons are added. For the other elements, d-orbit resources.

Ionization energy energy

The electrons have a certain amount of energy which they are assigned, and this energy is the distance from the core. When the energy is converted into an electron, an electron May increase the distance of the nucleus, or even to escape the core. In the latter case, the atom a positive charged ion. The amount of energy that is necessary is that an electron ionization energy of the atom is energy. Therefore, the irradiation of energy needed to an electron in an orbit outside of an atom is smaller than an electron, which is closer to the core.

The density of an element is represented by a series on how the question of an element are atoms around their average. The density of the individual elements can not be compared with the same volume. Depends on the density and volume.

Units of density are often kg/m3 og/cm3. The density of a number of materials are included in the tables.

At first glance there are many elements that have certain features. A close comparison of these functions, including color, state of matter (solid, liquid or gaseous), the smell, the fire and the density of substances to identify the others. If the materials are compared and contrasted characteristics that can be used in groups. The large corporations that deal with the chemical industry are: acids, alkalis, oxides, salts, metals, oil and polymers (eg, with a large number of atoms, which their models on a regular basis.

Molecules and the grains beauty

The smallest chemical potential is determined by the merger of a number of atoms - a means - as a molecule. If we have a certain amount of material to decide if yes or no, they produce a certain amount depending on the mass, volume or quantity of the particles.

In chemistry, we used the variable (s), very often as a measure of the quantity of a substance. A unit of a material is a grain of beauty. We can imagine that the quantity of a substance in a dozen chemicals, including one unit, so to speak. And, as a dozen or 12, a grain of beauty is always equal to a number of particles. Of course, this figure of more than 12 minutes, because the size of atoms and molecules. It would be difficult, in multiples of 12

A grain of beauty is a 6022 x 10 23 particles. This seemingly arbitrary number of particles is a chemical used on the truth, the use of carbon (chemical symbol C), since this element plays one of, if not the most important role in chemistry. Twelve grams (g) of the element carbon contains exactly 1 mole of atoms. Why the number of the smallest particle a large role in the chemistry? The answer to this question has to do with the nature and types of chemical reactions. In the course of a chemical reaction, the particles interact with other, often in combination to form a new substance. For example, water, is the combination, or one of two atoms, two hydrogen atoms and one oxygen atom. The mass of these two elements are not reactive enough to hold a sufficient quantity of each element in the combination, since the oxygen atoms are much heavier than hydrogen atoms.

In the laboratory, a pharmacy is not the quantity of a substance by deduction or a kind of instinct. The quantity of a substance in May, however, by its mass, which is directly related to the quantity of particles a certain quantity of the substance. The report on a certain amount of mass (m) and the quantity (n) is the molar mass (M), with a range of g / mol.

Molecular weight is determined by the sum of the masses of the atoms in a molecule. Atomic masses slightly from the Periodic Table of Elements. (Hydrogen (H) 1g/mol, helium (He) 4 g / mol, lithium (Li) 7g/mol, beryllium (Be) 9 g / mol, etc..) See Periodic Table atomic weight.

The molecular weight of water (H2O) at 18 g / mol: 1g/mol for each hydrogen atom (H) and 16 g / mol to an oxygen atom (O). The molecule consists of three atoms (2H + 1 O), or simply three parts which are to form atoms or the molecule. The number of particles of 1 mol of water 6022nd 10 23 water molecules.

The atoms of different elements have the same mass. The variable of the masses of the molecules depends on the ability to bind molecules of the components of atoms and their atomic weight.

Matter, or the mass neither created nor destroyed. If, in the course of chemical reactions: one, or other products of the reaction that they have less mass than the reagent, probably one of the products are not easily recognizable - perhaps invisible, odorless gas, or any other product of the reaction. Comparing with the scientificalness the mass of all materials as a function of the mass of all manufactured products, the same amount is still on both sides. Issue neither created nor destroyed, but can not change form.

A mixture of material in a liquid solution is a solution. These mixtures can be measured by the volume. The quantity of dissolved in the same volume of a solution can be composed of a mixture of others. In determining the amount of a substance dissolved in a solution, we use the chemical concentration (symbol: C), a measure of strength varies. "The unity of a number of moles dissolved in one liter of solution. The concentration of the substance is that the concentration of a substance in the solution. The ratio is the amount of dissolved in a given volume of solution (12 g carbon (C) in a liters of water at a concentration of 1 mol / l). We call this sum for the solution of a molar solution of carbon and short, 1 M.

To determine the molar solution, or in the event of a chemical that will need a solution to a certain molar concentration, it is necessary to calculate the mass of each material. The mass of the substance is dissolved in the necessary hardware, and the mass of the molecular weight of the material. The quantity of a substance in a solution can be calculated from the concentration of a substance and the volume of the solution.

For example, a solution of 1 molar salt we need 58.5 g of salt in 1 liter of water. Table salt is a sodium and chlorine. The chemical formula of this particular NaCl. The mass mole of NaCl is of 58.5 grams, such as sodium (Na) has a molecular weight of 23 g of chlorine (Cl) an atomic mass of 35.5 g. The two together (23 + 35.5 = 58.5). The molecular weight is easy from the Periodic Table of Elements.

A certain molar concentration does not say how a given volume of solution. Ie a 1 molar there is no guarantee that 1 liter of solution. However, a 1 M means that the proportion of dissolved substance (solution) to the volume of the dissolved substance (solvent). In our example, the salt, then instead of 58.5 g NaCl in 1 liter of water, if you had just served, 29.25 g NaCl, 0.5 l water or 117 g of salt and 2 gallons of water.

Chemical symbols

Substances and chemical reactions can be simply and directly in the chemistry. A system of symbols, abbreviations and chemical formulas are used which are all internationally recognized - by a committee of experts who have agreed to these symbols. In a first step, but somewhat abstract symbols were used. The circular symbols, the connections were used. Today, the system was by JJ Berzeliem (Swedish chemist, 1779-1848). In this system, each element has a symbol chemical, usually in Latin or Greek (eg, magnesium - Mg = oxygen or Oxygenium - O).

The elements consist of small particles of the same type. We call these particles atoms. In some parts, the atoms combine, in its natural state in two or even more, an element is off. In this case, the atoms of an element are closely linked, creating a greater chemical stability. We call these combinations of molecules and molecular substances. Small molecules are often the basic elements

gaseous or liquid. For example, the elements hydrogen, nitrogen and oxygen are still together, in pairs of two. There are molecules, however, are different elements. The area "water" is an oxygen atom and two hydrogen atoms.

An important basis of the chemical terminology, the concept of using small quantities of a chemical element to maximize the number of atoms, known as stoichiometry. In the language of chemical symbols, a symbol of an element is often associated with these issues, and is a chemical formula. A formula, then the part of one of the symbols, consisting of. And after each element symbol, the number of atoms of the element in the plant is. This number is smaller than the symbol. Some, such as an atom of an element is self-evident and therefore is not written, such as the chemical formula of water, H2O, defined as two hydrogen atoms and one oxygen atom. The water is not written that H2O1.

The formula is a connection through the material and he has with his constituents, which are produced. At the level of the particles, the formula in the molecule and the sum of all the atoms in the molecule, and their relationships to each other. The relationship between the number of atoms in a molecule can be calculated, for example with the help of the mass of the individual elements and their atomic weight.

Stoichiometry said that the atoms of a mutually linked to fixed.

1. The law of Dalton: The ratio of the masses of the two elements, which in a molecule may be replaced by a whole number.

2. The law to be adopted: each component contains specific mass and constant.

3 The Law of the proportions compatible: the elements together, proportional masses or numbers.

How many atoms of an element combines with the number of atoms of another element may be offset by experience and calculation. The true chemical formula for a series of connections and can not be identified easily, but if we know that the chances for the reunification of the individual (the value). That is the crucial factor for the individual elements. For example, if we know that the possibilities for a union, you can specify the number of hydrogen atoms to link. The valency of an element in conjunction with hydrogen occurs when the odd number of electrons in the outer electron cloud (cloud of electrons moving in a certain amount or in an orbit around the nucleus). For example, in water (H2O) and an oxygen atom (O) compounds with two hydrogen atoms (H) and therefore has a value of 2

In the chemical bonds of the atoms, not just add the numbers, but the ratio of the mass remains constant. For example, the chemical reaction of iron (Fe) are the sulfur (S), iron sulfide (FeS) is trained. The relationship between the number of atoms is 1:1. The ratio of the mass of individual atoms in the atomic mass of sulfur and iron, and 1.45 (7:4).

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