Arsenic in the table. Pronunciation of the symbol as the name of the element sounds in Latin

2.1. Chemical language and its parts

Humanity uses many different languages. Except natural languages(Japanese, English, Russian - more than 2.5 thousand in total), there are also artificial languages, for example, Esperanto. Among artificial languages there are languages various sciences. So, in chemistry they use their own, chemical language.
Chemical language– a system of symbols and concepts designed for a brief, succinct and visual recording and transmission of chemical information.
A message written in most natural languages is divided into sentences, sentences into words, and words into letters. If we call sentences, words and letters parts of language, then we can identify similar parts in chemical language (Table 2).

Table 2.Parts of chemical language

It is impossible to master any language immediately; this also applies to a chemical language. Therefore, for now you will only get acquainted with the basics of this language: learn some “letters”, learn to understand the meaning of “words” and “sentences”. At the end of this chapter you will be introduced to names chemical substances are an integral part of the chemical language. As you study chemistry, your knowledge of chemical language will expand and deepen.

CHEMICAL LANGUAGE.
1.What artificial languages do you know (other than those mentioned in the text of the textbook)?
2.How do natural languages differ from artificial ones?
3. Do you think it is possible to describe chemical phenomena without using chemical language? If not, why not? If so, what would be the advantages and disadvantages of such a description?

2.2. Chemical element symbols

The symbol for a chemical element represents the element itself or one atom of that element.
Each such symbol is an abbreviated Latin name of a chemical element, consisting of one or two letters of the Latin alphabet ( Latin alphabet see Appendix 1). The symbol is written with a capital letter. Symbols, as well as Russian and Latin names of some elements, are given in Table 3. Information about the origin of the Latin names is also given there. General rule there is no pronunciation of the symbols, therefore Table 3 also shows the “reading” of the symbol, that is, how this symbol is read in the chemical formula.

It is impossible to replace the name of an element with a symbol in oral speech, but in handwritten or printed texts this is allowed, but not recommended. Currently, 110 chemical elements are known, 109 of them have names and symbols approved by the International Union of Pure and Applied Chemistry (IUPAC).
Table 3 provides information on only 33 elements. These are the elements that you will encounter first when studying chemistry. Russian names (in alphabetical order) and symbols of all elements are given in Appendix 2.

Table 3.Names and symbols of some chemical elements

Name
	Latin		Writing
-	Writing	Origin	-	-
Nitrogen	N itrogenium	From Greek "giving birth to saltpeter"		"en"
Aluminum	Al uminium	From lat. "alum"		"aluminum"
Argon	Ar gon	From Greek "inactive"		"argon"
Barium	Ba rium	From Greek " heavy"		"barium"
Bor	B orum	From Arabic "white mineral"		"boron"
Bromine	Br omum	From Greek "smelly"		"bromine"
Hydrogen	H hydrogenium	From Greek "giving birth to water"		"ash"
Helium	He lium	From Greek " Sun"		"helium"
Iron	Fe rrum	From lat. "sword"		"ferrum"
Gold	Au rum	From lat. "burning"		"aurum"
Iodine	I odum	From Greek " violet"		" iodine"
Potassium	K alium	From Arabic "lye"		"potassium"
Calcium	Ca lcium	From lat. "limestone"		"calcium"
Oxygen	O xygenium	From Greek "acid-generating"		" O"
Silicon	Si licium	From lat. "flint"		"silicium"
Krypton	Kr ypton	From Greek "hidden"		"krypton"
Magnesium	M a g nesium	From the name Magnesia Peninsula		"magnesium"
Manganese	M a n ganum	From Greek "cleansing"		"manganese"
Copper	Cu prum	From Greek name O. Cyprus		"cuprum"
Sodium	Na trium	From Arabic, "detergent"		"sodium"
Neon	Ne on	From Greek " new"		"neon"
Nickel	Ni ccolum	From him. "St. Nicholas Copper"		"nickel"
Mercury	H ydrar g yrum	Lat. "liquid silver"		"hydrargyrum"
Lead	P lum b um	From lat. names of an alloy of lead and tin.		"plumboom"
Sulfur	S ulfur	From Sanskrit "combustible powder"		"es"
Silver	A r g entum	From Greek " light"		"argentum"
Carbon	C arboneum	From lat. " coal"		"tse"
Phosphorus	P hosphorus	From Greek "bringer of light"		"peh"
Fluorine	F luorum	From lat. verb "to flow"		"fluorine"
Chlorine	Cl orum	From Greek "greenish"		"chlorine"
Chromium	C h r omium	From Greek " dye"		"chrome"
Cesium	C ae s ium	From lat. "sky blue"		"cesium"
Zinc	Z i n cum	From him. "tin"		"zinc"

2.3. Chemical formulas

Used to designate chemical substances chemical formulas.

For molecular substances, a chemical formula can denote one molecule of this substance.
Information about a substance may vary, so there are different types of chemical formulas.
Depending on the completeness of the information, chemical formulas are divided into four main types: protozoa, molecular, structural And spatial.

Subscripts in the simplest formula do not have a common divisor.
The index "1" is not used in formulas.
Examples of the simplest formulas: water - H 2 O, oxygen - O, sulfur - S, phosphorus oxide - P 2 O 5, butane - C 2 H 5, phosphoric acid - H 3 PO 4, sodium chloride (table salt) - NaCl.
The simplest formula of water (H 2 O) shows that the composition of water includes the element hydrogen(H) and element oxygen(O), and in any portion (a portion is a part of something that can be divided without losing its properties.) of water, the number of hydrogen atoms is twice the number of oxygen atoms.
Number of particles, including number of atoms, denoted Latin letter N. Denoting the number of hydrogen atoms – N H, and the number of oxygen atoms is N O, we can write that

Or N H: N O=2:1.

The simplest formula of phosphoric acid (H 3 PO 4) shows that phosphoric acid contains atoms hydrogen, atoms phosphorus and atoms oxygen, and the ratio of the numbers of atoms of these elements in any portion of phosphoric acid is 3:1:4, that is

NH: N P: N O=3:1:4.

The simplest formula can be compiled for any individual chemical substance, and for molecular substance, in addition, can be compiled molecular formula.

Examples molecular formulas: water – H 2 O, oxygen – O 2, sulfur – S 8, phosphorus oxide – P 4 O 10, butane – C 4 H 10, phosphoric acid – H 3 PO 4.

Non-molecular substances do not have molecular formulas.

The sequence of writing element symbols in simple and molecular formulas is determined by the rules of chemical language, which you will become familiar with as you study chemistry. The information conveyed by these formulas is not affected by the sequence of symbols.

Of the signs reflecting the structure of substances, we will only use for now valence stroke("dash"). This sign shows the presence between the atoms of the so-called covalent bond(what type of connection this is and what its features are, you will soon find out).

In a water molecule, an oxygen atom is connected by simple (single) bonds to two hydrogen atoms, but the hydrogen atoms are not connected to each other. This is what clearly shows structural formula water.

Another example: the sulfur molecule S8. In this molecule, 8 sulfur atoms form an eight-membered ring, in which each sulfur atom is connected to two other atoms by simple bonds. Compare the structural formula of sulfur with the three-dimensional model of its molecule shown in Fig. 3. Please note that the structural formula of sulfur does not convey the shape of its molecule, but only shows the sequence of connection of atoms by covalent bonds.

The structural formula of phosphoric acid shows that in the molecule of this substance one of the four oxygen atoms is connected only to the phosphorus atom by a double bond, and the phosphorus atom, in turn, is connected to three more oxygen atoms by single bonds. Each of these three oxygen atoms is also connected by a simple bond to one of the three hydrogen atoms present in the molecule.

Compare the following three-dimensional model of a methane molecule with its spatial, structural and molecular formula:

In the spatial formula of methane, wedge-shaped valence strokes, as if in perspective, show which of the hydrogen atoms is “closer to us” and which is “further from us”.

Sometimes the spatial formula indicates bond lengths and angles between bonds in a molecule, as is shown in the example of a water molecule.

Non-molecular substances do not contain molecules. For the convenience of carrying out chemical calculations in a non-molecular substance, the so-called formula unit.

Examples of the composition of formula units of some substances: 1) silicon dioxide (quartz sand, quartz) SiO 2 – a formula unit consists of one silicon atom and two oxygen atoms; 2) sodium chloride (table salt) NaCl – the formula unit consists of one sodium atom and one chlorine atom; 3) iron Fe - a formula unit consists of one iron atom. Like a molecule, a formula unit is the smallest portion of a substance that retains its chemical properties.

Table 4

Information conveyed by different types of formulas

Formula type

Information conveyed by the formula.

The simplest

Molecular

Structural

Spatial

The atoms of which elements make up the substance.
Relationships between the numbers of atoms of these elements.
The number of atoms of each element in a molecule.
Types of chemical bonds.
The sequence of joining atoms by covalent bonds.
Multiplicity of covalent bonds.
Mutual arrangement atoms in space.
Bond lengths and angles between bonds (if specified).

Let us now consider, using examples, what information different types of formulas give us.

1. Substance: acetic acid. The simplest formula is CH 2 O, molecular formula is C 2 H 4 O 2, structural formula

The simplest formula tells us that
1) acetic acid contains carbon, hydrogen and oxygen;
2) in this substance the number of carbon atoms relates to the number of hydrogen atoms and the number of oxygen atoms, as 1: 2: 1, that is N H: N C: N O = 1:2:1.
Molecular formula adds that
3) in a molecule of acetic acid there are 2 carbon atoms, 4 hydrogen atoms and 2 oxygen atoms.
Structural formula adds that
4, 5) in a molecule two carbon atoms are connected to each other by a simple bond; one of them, in addition, is connected to three hydrogen atoms, each with a single bond, and the other to two oxygen atoms, one with a double bond and the other with a single bond; the last oxygen atom is still connected by a simple bond to the fourth hydrogen atom.

2. Substance: sodium chloride. The simplest formula is NaCl.
1) Sodium chloride contains sodium and chlorine.
2) In this substance, the number of sodium atoms is equal to the number of chlorine atoms.

3. Substance: iron. The simplest formula is Fe.
1) This substance contains only iron, that is, it is a simple substance.

4. Substance: trimetaphosphoric acid . The simplest formula is HPO 3, molecular formula is H 3 P 3 O 9, structural formula

1) Trimetaphosphoric acid contains hydrogen, phosphorus and oxygen.
2) N H: N P: N O = 1:1:3.
3) The molecule consists of three hydrogen atoms, three phosphorus atoms and nine oxygen atoms.
4, 5) Three phosphorus atoms and three oxygen atoms, alternating, form a six-membered cycle. All connections in the cycle are simple. Each phosphorus atom is, in addition, connected to two more oxygen atoms, one with a double bond and the other with a single bond. Each of the three oxygen atoms connected by simple bonds to phosphorus atoms is also connected by a simple bond to a hydrogen atom.

Phosphoric acid – H 3 PO 4(another name is orthophosphoric acid) is a transparent, colorless, crystalline substance of molecular structure that melts at 42 o C. This substance dissolves very well in water and even absorbs water vapor from the air (hygroscopic). Phosphoric acid is produced in large quantities and is used primarily in the production of phosphate fertilizers, as well as in chemical industry, in the production of matches and even in construction. In addition, phosphoric acid is used in the manufacture of cement in dental equipment and is part of many medicines. This acid is quite cheap, so in some countries, such as the United States, very pure phosphoric acid, highly diluted with water, is added to refreshing drinks to replace the expensive citric acid.

Methane - CH 4. If you have a gas stove at home, then you encounter this substance every day: natural gas The gas that burns on your stove burners is 95% methane. Methane is a colorless and odorless gas with a boiling point of –161 o C. When mixed with air, it is explosive, which explains the explosions and fires that sometimes occur in coal mines (another name for methane is firedamp). The third name for methane - swamp gas - is due to the fact that bubbles of this particular gas rise from the bottom of swamps, where it is formed as a result of the activity of certain bacteria. In industry, methane is used as fuel and raw material for the production of other substances. Methane is the simplest hydrocarbon

. This class of substances also includes ethane (C 2 H 6), propane (C 3 H 8), ethylene (C 2 H 4), acetylene (C 2 H 2) and many other substances..Table 5-

Examples of different types of formulas for some substances

Bess Ruff is a graduate student from Florida working toward a PhD in geography. She received her Master's degree in Environmental Science and Management from the Bren School of Environmental Science and Management at the University of California, Santa Barbara in 2016.

Number of sources used in this article: . You will find a list of them at the bottom of the page. If you find the periodic table difficult to understand, you are not alone! Although it can be difficult to understand its principles, knowing how to use it will help you learn natural sciences

. First, study the structure of the table and what information you can learn from it about each chemical element. Then you can begin to study the properties of each element. And finally, using the periodic table, you can determine the number of neutrons in an atom of a particular chemical element.

Steps

Part 1

Table structure Periodic table, or periodic table chemical elements, begins in the upper left corner and ends at the end of the last row of the table (lower right corner)..

As you can see, each subsequent element contains one more proton than the element preceding it. This is obvious when you look at the atomic numbers. Atomic numbers increase by one as you move from left to right. Because elements are arranged in groups, some table cells are left empty.
- For example, the first row of the table contains hydrogen, which has atomic number 1, and helium, which has atomic number 2. However, they are located on opposite edges because they belong to different groups.
Learn about groups that contain elements with similar physical and chemical properties. The elements of each group are located in the corresponding vertical column. They are typically identified by the same color, which helps identify elements with similar physical and chemical properties and predict their behavior. All elements of a particular group have the same number of electrons in their outer shell.
- Hydrogen can be classified as both alkali metals and halogens. In some tables it is indicated in both groups.
- In most cases, the groups are numbered from 1 to 18, and the numbers are placed at the top or bottom of the table. Numbers can be specified in Roman (eg IA) or Arabic (eg 1A or 1) numerals.
- When moving along a column from top to bottom, you are said to be “browsing a group.”
Find out why there are empty cells in the table. Elements are ordered not only according to their atomic number, but also by group (elements in the same group have similar physical and chemical properties). Thanks to this, it is easier to understand how a particular element behaves. However, as the atomic number increases, elements that fall into the corresponding group are not always found, so there are empty cells in the table.
- For example, the first 3 rows have empty cells because transition metals found only from atomic number 21.
- Elements with atomic numbers 57 to 102 are classified as rare earth elements, and are usually placed in their own subgroup in the lower right corner of the table.
Each row of the table represents a period. All elements of the same period have the same number of atomic orbitals in which the electrons in the atoms are located. The number of orbitals corresponds to the period number. The table contains 7 rows, that is, 7 periods.
- For example, atoms of elements of the first period have one orbital, and atoms of elements of the seventh period have 7 orbitals.
- As a rule, periods are designated by numbers from 1 to 7 on the left of the table.
- As you move along a line from left to right, you are said to be “scanning the period.”
Learn to distinguish between metals, metalloids and non-metals. You will better understand the properties of an element if you can determine what type it is. For convenience, in most tables metals, metalloids, and nonmetals are designated by different colors. Metals are on the left and non-metals are on the right side of the table. Metalloids are located between them.

Part 2
Element designations
1. Each element is designated by one or two Latin letters. As a rule, the element symbol is shown in large letters in the center of the corresponding cell. A symbol is a shortened name for an element that is the same in most languages. When conducting experiments and working with chemical equations element symbols are commonly used, so it is useful to remember them.
  - Typically, element symbols are abbreviations of their Latin name, although for some, especially recently discovered elements, they are derived from the common name. For example, helium is represented by the symbol He, which is close to the common name in most languages. At the same time, iron is designated as Fe, which is an abbreviation of its Latin name.
2. Pay attention to the full name of the element if it is given in the table. This element "name" is used in regular texts. For example, "helium" and "carbon" are names of elements. Usually, although not always, the full names of the elements are listed below their chemical symbol.
  - Sometimes the table does not indicate the names of the elements and only gives their chemical symbols.
3. Find the atomic number. Typically, the atomic number of an element is located at the top of the corresponding cell, in the middle or in the corner. It may also appear under the element's symbol or name. Elements have atomic numbers from 1 to 118.
  - The atomic number is always an integer.
4. Remember that the atomic number corresponds to the number of protons in an atom. All atoms of an element contain the same number of protons. Unlike electrons, the number of protons in the atoms of an element remains constant. Otherwise it would have been different chemical element!
  - The atomic number of an element can also determine the number of electrons and neutrons in an atom.
5. Usually the number of electrons is equal to the number of protons. The exception is the case when the atom is ionized. Protons have a positive charge and electrons have a negative charge. Because atoms are usually neutral, they contain the same number of electrons and protons. However, an atom can gain or lose electrons, in which case it becomes ionized.
  - Ions have electric charge. If an ion has more protons, it has a positive charge, in which case a plus sign is placed after the element symbol. If an ion contains more electrons, it has a negative charge, indicated by a minus sign.
  - The plus and minus signs are not used if the atom is not an ion.

How to use the periodic table? For an uninitiated person, reading the periodic table is the same as for a gnome looking at the ancient runes of the elves. And the periodic table, by the way, if used correctly, can tell a lot about the world. In addition to serving you well in the exam, it is also simply irreplaceable in solving a huge number of chemical and physical problems. But how to read it? Fortunately, today everyone can learn this art. In this article we will tell you how to understand the periodic table.

The periodic table of chemical elements (Mendeleev's table) is a classification of chemical elements that establishes the dependence of various properties of elements on the charge of the atomic nucleus.

History of the creation of the Table

Dmitry Ivanovich Mendeleev was not a simple chemist, if anyone thinks so. He was a chemist, physicist, geologist, metrologist, ecologist, economist, oil worker, aeronaut, instrument maker and teacher. During his life, the scientist managed to conduct a lot of fundamental research in various fields of knowledge. For example, it is widely believed that it was Mendeleev who calculated the ideal strength of vodka - 40 degrees. We don’t know how Mendeleev felt about vodka, but we know for sure that his dissertation on the topic “Discourse on the combination of alcohol with water” had nothing to do with vodka and considered alcohol concentrations from 70 degrees. With all the merits of the scientist, the discovery of the periodic law of chemical elements - one of the fundamental laws of nature, brought him the widest fame.

There is a legend according to which a scientist dreamed of the periodic table, after which all he had to do was refine the idea that had appeared. But, if everything were so simple.. This version of the creation of the periodic table, apparently, is nothing more than a legend. When asked how the table was opened, Dmitry Ivanovich himself answered: “ I’ve been thinking about it for maybe twenty years, but you think: I was sitting there and suddenly... it’s done.”

In the mid-nineteenth century, attempts to arrange the known chemical elements (63 elements were known) were undertaken in parallel by several scientists. For example, in 1862, Alexandre Emile Chancourtois placed elements along a helix and noted cyclic repetition chemical properties. Chemist and musician John Alexander Newlands proposed his version of the periodic table in 1866. An interesting fact is that the scientist tried to discover some kind of mystical musical harmony in the arrangement of the elements. Among other attempts, there was also Mendeleev’s attempt, which was crowned with success.

In 1869, the first table diagram was published, and March 1, 1869 is considered the day the periodic law was opened. The essence of Mendeleev's discovery was that the properties of elements with increasing atomic mass do not change monotonically, but periodically. The first version of the table contained only 63 elements, but Mendeleev undertook a number of very non-standard solutions. So, he guessed to leave space in the table for still undiscovered elements, and also changed the atomic masses of some elements. The fundamental correctness of the law derived by Mendeleev was confirmed very soon, after the discovery of gallium, scandium and germanium, the existence of which was predicted by the scientist.

Modern view of the periodic table

Below is the table itself

Today, instead of atomic weight (atomic mass), the concept of atomic number (the number of protons in the nucleus) is used to order elements. The table contains 120 elements, which are arranged from left to right in order of increasing atomic number (number of protons)

The table columns represent so-called groups, and the rows represent periods. The table has 18 groups and 8 periods.

The metallic properties of elements decrease when moving along a period from left to right, and increase in the opposite direction.
The sizes of atoms decrease when moving from left to right along periods.
As you move from top to bottom through the group, the reducing metal properties increase.
Oxidizing and non-metallic properties increase when moving along a period from left to right I.

What do we learn about an element from the table? For example, let's take the third element in the table - lithium, and consider it in detail.

First of all, we see the element symbol itself and its name below it. In the upper left corner is the atomic number of the element, in which order the element is arranged in the table. The atomic number, as already mentioned, equal to the number protons in the nucleus. The number of positive protons is usually equal to the number of negative electrons in an atom (except in isotopes).

The atomic mass is indicated under the atomic number (in this version of the table). If we round the atomic mass to the nearest integer, we get what is called the mass number. The difference between the mass number and the atomic number gives the number of neutrons in the nucleus. Thus, the number of neutrons in a helium nucleus is two, and in lithium it is four.

Our course “Periodical Table for Dummies” has ended. In conclusion, we invite you to watch a thematic video, and we hope that the question of how to use periodic table Mendeleev, has become more clear to you. We remind you that it is always more effective to study a new subject not alone, but with the help of an experienced mentor. That is why you should never forget about them, who will gladly share their knowledge and experience with you.

Some who died from cholera in the Middle Ages did not die from it. Symptoms of the disease are similar to those arsenic poisoning.

Having realized this, medieval businessmen began to offer the trioxide of the element as a poison. Substance. The lethal dose is only 60 grams.

They were divided into portions, given over several weeks. As a result, no one suspected that the man did not die from cholera.

The taste of arsenic is not felt in small doses, such as in food or drinks. In modern realities, of course, there is no cholera.

People don't have to worry about arsenic. Rather, it is the mice who need to be afraid. A toxic substance is a type of poison for rodents.

By the way, the element is named in their honor. The word “arsenic” exists only in Russian-speaking countries. The official name of the substance is arsenicum.

Designation in – As. The serial number is 33. Based on it, we can assume full list properties of arsenic. But let's not assume. We'll look into the issue for sure.

Properties of arsenic

The Latin name of the element translates as “strong”. Apparently, this refers to the effect of the substance on the body.

When intoxicated, vomiting begins, digestion is upset, the stomach twists and work is partially blocked nervous system. not one of the weak ones.

Poisoning occurs from any of the allotropic forms of the substance. Alltropy is the existence of manifestations of the same thing that are different in structure and properties. element. Arsenic most stable in metal form.

Steel-gray rhombohedral ones are fragile. The units have a characteristic metallic appearance, but upon contact with moist air they become dull.

Arsenic - metal, whose density is almost 6 grams per cubic centimeter. The remaining forms of the element have a lower indicator.

In second place is amorphous arsenic. Element characteristics: - almost black color.

The density of this form is 4.7 grams per cubic centimeter. Externally, the material resembles.

The usual state of arsenic for ordinary people is yellow. Cubic crystallization is unstable and becomes amorphous when heated to 280 degrees Celsius, or under the influence of simple light.

Therefore, yellow ones are soft, like in the dark. Despite the color, the aggregates are transparent.

From a number of modifications of the element it is clear that it is only half a metal. The obvious answer to the question is: “ Arsenic is a metal or non-metal", No.

Serve as confirmation chemical reactions. The 33rd element is acid-forming. However, being in acid itself does not give.

Metals do things differently. In the case of arsenic, they do not work out even upon contact with one of the strongest.

Salt-like compounds are “born” during the reactions of arsenic with active metals.

This refers to oxidizing agents. The 33rd substance interacts only with them. If the partner does not have expressed oxidative properties, the interaction will not take place.

This even applies to alkalis. That is, arsenic is a chemical element quite inert. How then can you get it if the list of reactions is very limited?

Arsenic mining

Arsenic is mined as a by-product of other metals. They are separated, leaving the 33rd substance.

In nature there are compounds of arsenic with other elements. It is from them that the 33rd metal is extracted.

The process is profitable, because together with arsenic there are often , , and .

It is found in granular masses or cubic crystals of tin color. Sometimes there is a yellow tint.

Arsenic compound And metal Ferrum has a “brother”, in which instead of the 33rd substance there is . This is an ordinary pyrite with a golden color.

The aggregates are similar to the arsenic version, but cannot serve as arsenic ore, although they also contain arsenic as an impurity.

By the way, arsenic also occurs in ordinary water, but, again, as an impurity.

The amount of element per ton is so small, but even by-product mining makes no sense.

If the world's arsenic reserves were distributed evenly across earth's crust, you get only 5 grams per ton.

So, the element is not common; its quantity is comparable to , , .

If you look at the metals with which arsenic forms minerals, then this is not only with cobalt and nickel.

Total number minerals of the 33rd element reaches 200. A native form of the substance is also found.

Its presence is explained by the chemical inertness of arsenic. Forming next to elements with which reactions are not provided, the hero remains in splendid isolation.

In this case, needle-shaped or cubic aggregates are often obtained. Usually, they grow together.

Use of arsenic

The element arsenic belongs to dual, not only exhibiting properties of both metal and non-metal.

The perception of the element by humanity is also dual. In Europe, the 33rd substance has always been considered a poison.

In 1733, they even issued a decree prohibiting the sale and purchase of arsenic.

In Asia, the “poison” has been used by doctors for 2000 years in the treatment of psoriasis and syphilis.

Modern doctors have proven that the 33rd element attacks proteins that provoke oncology.

In the 20th century, some European doctors also sided with the Asians. In 1906, for example, Western pharmacists invented the drug salvarsan.

It became the first in official medicine and was used against a number of infectious diseases.

True, immunity to the drug, like any constant intake of arsenic in small doses, is developed.

1-2 courses of the drug are effective. If immunity has developed, people can take a lethal dose of the element and remain alive.

In addition to doctors, metallurgists became interested in the 33rd element and began adding it to produce shot.

It is made on the basis which is included in heavy metals. Arsenic increases the lead and allows its splashes to take a spherical shape when casting. It is correct, which improves the quality of the fraction.

Arsenic can also be found in thermometers, or rather in them. It is called Viennese, mixed with the oxide of the 33rd substance.

The compound serves as a clarifier. Arsenic was also used by glassblowers of antiquity, but as a matting additive.

Glass becomes opaque when there is a significant admixture of a toxic element.

Observing proportions, many glassblowers fell ill and died prematurely.

And tannery specialists use sulfides arsenic.

Element main subgroups Group 5 of the periodic table is included in some paints. In the leather industry, arsenicum helps remove hair from.

Arsenic price

Pure arsenic is most often offered in metallic form. Prices are set per kilogram or ton.

1000 grams costs about 70 rubles. For metallurgists, they offer ready-made, for example, arsenic and copper.

In this case, they charge 1500-1900 rubles per kilo. Arsenic anhydrite is also sold in kilograms.

It is used as a skin medicine. The agent is necrotic, that is, it numbs the affected area, killing not only the causative agent of the disease, but also the cells themselves. The method is radical, but effective.

Arsenic is a chemical element of the nitrogen group (group 15 of the periodic table). It is a brittle substance, gray with a metallic luster (α-arsenic), with a rhombohedral crystal lattice. When heated to 600°C, As sublimates. When the vapor is cooled, a new modification appears - yellow arsenic. Above 270°C, all forms of As transform into black arsenic.

History of discovery

What arsenic was was known long before it was recognized as a chemical element. In the 4th century. BC e. Aristotle mentioned a substance called sandarac, which is now believed to be realgar, or arsenic sulfide. And in the 1st century AD. e. the writers Pliny the Elder and Pedanius Dioscorides described orpiment - the dye As 2 S 3. In the 11th century n. e. There were three varieties of “arsenic”: white (As 4 O 6), yellow (As 2 S 3) and red (As 4 S 4). The element itself was probably first isolated in the 13th century by Albertus Magnus, who noted the appearance of a metal-like substance when arsenicum, another name for As 2 S 3, was heated with soap. But there is no certainty that this natural scientist obtained pure arsenic. The first authentic evidence of pure isolation dates back to 1649. German pharmacist Johann Schroeder prepared arsenic by heating its oxide in the presence of coal. Later, Nicolas Lemery, a French physician and chemist, observed the formation of this chemical element by heating a mixture of its oxide, soap and potash. TO early XVIII century, arsenic was already known as a unique semimetal.

Prevalence

In the earth's crust, the concentration of arsenic is low and amounts to 1.5 ppm. It is found in soil and minerals and can be released into the air, water and soil through wind and water erosion. In addition, the element enters the atmosphere from other sources. As a result of volcanic eruptions, about 3 thousand tons of arsenic are released into the air per year, microorganisms form 20 thousand tons of volatile methylarsine per year, and as a result of the combustion of fossil fuels, 80 thousand tons are released over the same period.

Despite the fact that As is a deadly poison, it is an important component of the diet of some animals and, possibly, humans, although the required dose does not exceed 0.01 mg/day.

Arsenic is extremely difficult to convert into a water-soluble or volatile state. The fact that it is quite mobile means that large concentrations of the substance cannot appear in any one place. On the one hand, this is a good thing, but on the other hand, the ease with which it spreads is why arsenic contamination is becoming a bigger problem. Due to human activity, mainly through mining and smelting, the normally immobile chemical element migrates and can now be found in places other than its natural concentration.

The amount of arsenic in the earth's crust is about 5 g per ton. In space, its concentration is estimated to be 4 atoms per million silicon atoms. This element is widespread. A small amount of it is present in the native state. As a rule, arsenic formations with a purity of 90-98% are found together with metals such as antimony and silver. Most of it, however, is included in more than 150 different minerals - sulfides, arsenides, sulfoarsenides and arsenites. Arsenopyrite FeAsS is one of the most common As-containing minerals. Other common arsenic compounds are the minerals realgar As 4 S 4, orpiment As 2 S 3, lellingite FeAs 2 and enargite Cu 3 AsS 4. Arsenic oxide is also common. Most of this substance is a by-product of the smelting of copper, lead, cobalt and gold ores.

In nature, there is only one stable isotope of arsenic - 75 As. Among artificial radioactive isotopes 76 As is released with a half-life of 26.4 hours. Arsenic-72, -74 and -76 are used in medical diagnostics.

Industrial production and application

Metallic arsenic is obtained by heating arsenopyrite to 650-700 °C without air access. If arsenopyrite and other metal ores are heated with oxygen, then As easily combines with it, forming easily sublimated As 4 O 6, also known as “white arsenic”. The oxide vapor is collected and condensed, and later purified by repeated sublimation. Most As is produced by its reduction with carbon from white arsenic thus obtained.

Global consumption of arsenic metal is relatively small - only a few hundred tons per year. Most of what is consumed comes from Sweden. It is used in metallurgy due to its metalloid properties. About 1% arsenic is used in the production of lead shot as it improves the roundness of the molten drop. The properties of lead-based bearing alloys are improved in both thermal and mechanical characteristics, when they contain about 3% arsenic. The presence of small amounts of this chemical element in lead alloys hardens them for use in batteries and cable armor. Small arsenic impurities increase the corrosion resistance and thermal properties of copper and brass. In its pure form, the chemical elemental As is used for bronze coating and in pyrotechnics. Highly purified arsenic has applications in semiconductor technology, where it is used with silicon and germanium, and in the form of gallium arsenide (GaAs) in diodes, lasers and transistors.

As connections

Since the valence of arsenic is 3 and 5, and it has a range of oxidation states from -3 to +5, the element can form different kinds connections. Its most important commercially important forms are As 4 O 6 and As 2 O 5 . Arsenic oxide, commonly known as white arsenic, is a by-product of the roasting of copper, lead and some other metal ores, as well as arsenopyrite and sulfide ores. It is the starting material for most other compounds. It is also used in pesticides, as a decolorizing agent in glass production, and as a preservative for leathers. Arsenic pentoxide is formed when white arsenic is exposed to an oxidizing agent (such as nitric acid). It is the main ingredient in insecticides, herbicides and metal adhesives.

Arsine (AsH 3), a colorless poisonous gas composed of arsenic and hydrogen, is another known substance. The substance, also called arsenic hydrogen, is obtained by hydrolysis of metal arsenides and reduction of metals from arsenic compounds in acid solutions. It has found use as a dopant in semiconductors and as a chemical warfare agent. IN agriculture great importance have arsenic acid (H 3 AsO 4), lead arsenate (PbHAsO 4) and calcium arsenate [Ca 3 (AsO 4) 2], which are used for soil sterilization and pest control.

Arsenic is a chemical element that forms many organic compounds. Cacodyne (CH 3) 2 As−As(CH 3) 2, for example, is used in the preparation of the widely used desiccant (drying agent) cacodylic acid. Complex organic compounds of the element are used in the treatment of certain diseases, for example, amoebic dysentery caused by microorganisms.

Physical properties

What is arsenic in terms of it physical properties? In its most stable state, it is a brittle, steel-gray solid with low thermal and electrical conductivity. Although some forms of As are metal-like, classifying it as a nonmetal is a more accurate characterization of arsenic. There are other forms of arsenic, but they are not very well studied, especially the yellow metastable form, consisting of As 4 molecules, like white phosphorus P 4 . Arsenic sublimes at a temperature of 613 °C, and in the form of vapor it exists as As 4 molecules, which do not dissociate until a temperature of about 800 °C. Complete dissociation into As 2 molecules occurs at 1700 °C.

Atomic structure and ability to form bonds

The electronic formula of arsenic - 1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 4p 3 - resembles nitrogen and phosphorus in that there are five electrons in the outer shell, but it differs from them in having 18 electrons in the penultimate shell instead of two or eight. Adding 10 positive charges to the nucleus while filling five 3d orbitals often causes an overall decrease electronic cloud and increasing the electronegativity of elements. Arsenic in the periodic table can be compared with other groups that clearly demonstrate this pattern. For example, it is generally accepted that zinc is more electronegative than magnesium, and gallium than aluminum. However, in subsequent groups this difference decreases, and many do not agree that germanium is more electronegative than silicon, despite the abundance of chemical evidence. A similar transition from the 8- to 18-element shell from phosphorus to arsenic may increase electronegativity, but this remains controversial.

The similarity of the outer shell of As and P suggests that they can form 3 per atom in the presence of an additional unbonded electron pair. The oxidation state must therefore be +3 or -3, depending on the relative mutual electronegativity. The structure of arsenic also suggests the possibility of using the outer d-orbital to expand the octet, which allows the element to form 5 bonds. It is realized only when reacting with fluorine. Availability of a free electron pair for formation complex compounds(through electron donation) in the As atom is much less manifested than in phosphorus and nitrogen.

Arsenic is stable in dry air, but turns into a black oxide in humid air. Its vapors burn easily, forming As 2 O 3. What is free arsenic? It is practically unaffected by water, alkalis and non-oxidizing acids, but is oxidized nitric acid to state +5. Halogens and sulfur react with arsenic, and many metals form arsenides.

Analytical chemistry

The substance arsenic can be qualitatively detected in the form of yellow orpiment, which precipitates under the influence of a 25% solution of hydrochloric acid. Traces of As are typically determined by converting it to arsine, which can be detected using the Marsh test. Arsine thermally decomposes to form a black mirror of arsenic inside a narrow tube. According to the Gutzeit method, a sample impregnated with arsine darkens due to the release of mercury.

Toxicological characteristics of arsenic

The toxicity of the element and its derivatives varies widely, from the extremely toxic arsine and its organic derivatives to simply As, which is relatively inert. What arsenic is is evidenced by the use of its organic compounds as chemical warfare agents (lewisite), vesicant and defoliant (Agent Blue based on an aqueous mixture of 5% cacodylic acid and 26% of its sodium salt).

In general, derivatives of this chemical element irritate the skin and cause dermatitis. Protection from inhalation of arsenic-containing dust is also recommended, but most poisoning occurs through ingestion. Extremely permissible concentration As in dust over an eight-hour working day is 0.5 mg/m 3 . For arsine, the dose is reduced to 0.05 ppm. In addition to the use of compounds of this chemical element as herbicides and pesticides, the use of arsenic in pharmacology made it possible to obtain salvarsan, the first successful drug against syphilis.

Health effects

Arsenic is one of the most toxic elements. Inorganic compounds of this chemical in natural conditions found in small quantities. People can be exposed to arsenic through food, water, and air. Exposure may also occur through skin contact with contaminated soil or water.

People who work with it, live in homes built from wood treated with it, and on agricultural lands where pesticides have been used in the past are also susceptible to exposure.

Inorganic arsenic can cause a variety of health effects in humans, such as stomach and intestinal irritation, decreased production of red and white blood cells, skin changes, and lung irritation. It is believed that ingesting significant amounts of this substance may increase the chances of developing cancer, especially cancer of the skin, lungs, liver and lymphatic system.

Very high concentrations of inorganic arsenic cause infertility and miscarriages in women, dermatitis, decreased body resistance to infections, heart problems and brain damage. In addition, this chemical element can damage DNA.

The lethal dose of white arsenic is 100 mg.

Organic compounds of the element no cancer, no damage genetic code do not cause harm, but high doses can cause harm to human health, such as nervous disorders or abdominal pain.