all the chemical elements of the periodic table conventionally divided diagonal B - At metals and non-metals.This last in the minority, are located above and to the right border.Metals also explicitly quantitative advantage, their 118 known elements is greater than 80.
They all have similar physical properties combined aggregate state.However, there is an exception - the element mercury.About it and talk more.
Mercury: the position in the periodic system
This element occupies the cell in the table at number 80. This is the second group, the sub-groups, the sixth great period.It has an atomic weight of 200.59.There is a seven stable isotopes: 196, 198, 199, 200, 201, 202, 204.
refers to an element d-family, but not a transition, as last valence electrons fill the s-orbital.Mercury is a subgroup metals zinc and cadmium with Copernicium.
General characteristic element
chemical elements of the periodic table have strictly ordered arrangement, and each has its electron configuration of the atom, talking about its properties.Mercury is no exception.The structure of its outer electron shell and predvneshney following: 5s25p65d106s2.
possible oxidation state +1, 2.Oxides and hydroxides of mercury - a weakly basic, sometimes the nature of the amphoteric compound.The chemical symbol for the element №80 - Hg, Latin pronunciation "gidrargirum."Russian name is derived from the Proto-Slavic language in which it is translated as "rolling".Among other peoples, and the name of a different pronunciation.Often the element itself and formed them simple and complex substances called merkuratami Mercury.This name comes from the ancient times, when compared the Hg (element) with silver, gave him a second value after the gold.Sun - a symbol of aurum Au, Mercury - symbol gidrargirum Hg.
The ancient people to believe that there are seven basic metals, including mercury.A group of them are reflected in the celestial bodies.That is, gold is associated with the sun, iron - Mars, Mercury - Mercury and so on.
History of discovery
About Mercury has been known for about 1500 years BC.Even then, it was described as "liquid silver", moving, unusual and mysterious metal.To extract it, too, learned in ancient times.
course, to study its properties was not possible, because has not been formed as such chemicals.Mercury shrouded veil of mystery and magic, it was considered an unusual substance close to the silver, and the ability to turn into gold, if you make it hard.However, the way to get pure mercury in the solid state was not, and alchemical researches were unsuccessful.
main countries, where the most ancient times was used and extracted mercury is:
- China;
- Mesopotamia;
- India;
- Egypt.
However, to get the metal is in its pure form was only in the XVIII century, did the Swedish chemist Brandt.Neither they, nor up to this point have not been shown evidence of metallicity substance.This question is clarified Lomonosov and Brown.These are the first scientists were able to freeze the mercury and thus confirm that it is characterized by all the properties of metals - shine, conductivity, malleability and ductility, metal crystal lattice.
Today received a variety of compounds of mercury, it is used in different areas of technical production.
substance mercury
As simple substance is a liquid (under normal conditions), silver-white, mobile, volatile.A typical example where the liquid mercury is used in pure form, - a thermometer, thermometers for measuring the temperature.
Translated mercury in the solid state, it will be a translucent crystals, odorless.Vapours are colorless, very poisonous.
Physical properties The physical properties of the metal - it is the only representative of which under normal conditions can exist as a liquid.For all other properties, it is perfectly suited for the general characteristics of other representatives of the category.
The main properties are as follows.
- Appearance: normal conditions - liquid, solid crystals - no higher 352oS, couples - more than 79 K.
- soluble in benzene, dioxane, the crystals in the water.It has the ability not to wet the glass.
- has diamagnetic properties.
- conductivity.
melting mercury occurs at temperatures below freezing -38,83oS.Therefore, the substance belongs to the explosive when heated.The internal power supply connections thus increases several times.
boiling mercury starts at 356,73oS.At this point it begins to pass into the vapor state, which is completely invisible to the eye of the molecule joined nonpolar covalent bond.
Melting mercury shows that the properties of the metal clearly unusual.This material begins to evaporate, turning into invisible gaseous state molecules, even at normal room temperature, which makes it particularly dangerous for human and animal health.
chemical properties
Known group of compounds based on mercury in various oxidation states:
- sulphates, sulphides;
- chlorides;
- nitrates;
- hydroxides;
- oxides;
- complex compounds;
- organometallic substances;
- intermetallic;
- alloys with other metals - amalgam.
melting point of mercury allows it to form both liquid and solid amalgam.In such metal alloys lose their activity, becoming more inert.
The reaction of oxygen with mercury is possible only at a sufficiently high temperature, despite the strong oxidizing power of the nonmetal.Under the conditions of excess of 380oC a result of such synthesis of metal oxide is formed by oxidation of the last two.
with acids, alkalis, non-metals in the form of the free metal does not enter into chemical interaction, remaining in a liquid state.
with halogens reacts rather slowly and only in the cold, and confirms that the melting point of mercury.Good for her oxidant is potassium permanganate.
Being in nature
Contained in the earth's crust, the oceans, ores and minerals.If we talk about the percentage of the total mercury in the bowels of the earth, it is about 0.000001%.In general we can say that the element diffused.Basic minerals and ores, which include the metal, as follows:
- cinnabar;
- quartz;
- chalcedony;
- mica;
- carbonates;
- lead-zinc ores.
mercury in nature all the time makes the cycle and takes part in the metabolic processes of the Earth's shells.
Getting mercury
main way of getting - is the processing of the mineral cinnabar.It is also possible metallurgical method using reducing agents.When using the first method, the mineral is subjected to hard fired in oxygen.This produces metal vapor.Since the melting point of mercury is very low, while boiling, in contrast, is high, vapor condensation and collection on delivery calcining do not cause difficulties.This way of handling mercury sulfide was used in ancient times for the metal in its purest form.
second method is based on the extraction of mercury and sulfide through the use of a strong reducing agent.Such as iron.Collection of the product is carried out in the same manner as in the previous case.
biological effects on living organisms
temperature is low enough mercury need to go to the vapor state.This process begins at 25C, i.e. at normal room temperature.In this case, the presence of live organisms in the room becomes a health hazard.
Thus, the metal is able to penetrate through creatures:
- skin, intact, completely whole;
- mucous membranes;
- airways;
- digestive organs.
Once inside, the mercury vapor is included in the bloodstream, and then enter the synthesis of the protein and other molecules, forming compounds with them.Thus there is an accumulation of harmful metals in the liver and bone.Out of storage metal can once again be included in the metabolic processes, synthesis and degradation, causing a slow intoxication, accompanied by the most severe consequences.
Report from the authorities rather slowly and by the action of catalysts, adsorbents.For example, milk.Basic fluid through which the output of the metal to the environment:
- saliva;
- bile;
- urine;
- products of the gastrointestinal tract.
There are two main forms of the substance poisoning: acute and chronic.Each has its own characteristics and symptoms.
Symptoms and treatment
acute form is typical for cases when there is a spill of mercury in the production, there comes a time when a huge release of substances into the atmosphere.In such situations, vulnerable people is a sharp deterioration of health, that is poisoning.Symptoms following:
- inflamed respiratory system, the lungs, the mucous membranes of the mouth and throat.
- Increased body temperature.
- Ulcers form on the gums, they bleed, swell and become very sensitive.Sometimes mercury is formed rim.
- atrophy of the liver and kidneys.
- chills, nausea and vomiting, dizziness.
- nervous system suffers greatly - broken speech and coordination of movements, there is a tremor of the extremities.
- Poisoning is accompanied by headaches and diarrhea with blood inclusions.
If mercury vapor damage occurred gradually, the disease takes a chronic nature.In this case the symptoms are not as sharp, but the deterioration of health will accrue on a daily basis, taking all the larger momentum.
- Tremor of the limbs.
- diseases of the oral cavity (gingivitis, stomatitis, etc.).
- Hypertension and tachycardia.
- sweating.
- nervous excitement.
- Headaches.
- In severe cases, can be triggered by severe mental disorders, up to schizophrenia.
All of these effects can occur even due to a slight release of mercury into the atmosphere.If time does not hold demercurization premises, it is possible to greatly harm health.
Treatment in these cases is usually held the following medications:
- vitamins;
- antihistamines;
- barbiturates;
- "Aminazin."
Human uses
most common place of use and storage of metallic mercury - it thermometers and thermometers.In one such equipment may be up to 3 g of metal.In addition, you can highlight a few areas of human activity in which mercury is used widely:
- Medicine (calomel, merkuzal, promeran, many antiseptics);
- technical activities - current sources, incandescent lamps, pumps, barometers, detonator, and so on;
- foundries - evaporation of mirrors, jewelry of gold and silver amalgam, obtaining metal alloys, pure substances;
- chemical industry;
- agriculture.
Currently, because of the more safe and convenient mercury compounds practically forced out of medicine.
