Metal

gallium

of metals are the largest group of the chemical elements, about 80% of the elements are metals. They are generally good electrical conductor. In the periodic system of the elements they are assigned to certain rows or periods, on the contrary they are on the left of and below a line from the boron to the polonium. Right above the nonmetals are, between them the metalloids.

Table of contents

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metals in chemistry

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fundamental

metal of atoms are characterized by the following characteristics:

eV) that metal atoms cannot be connected like many nonmetals by atomic bonds to molecules or lattices. If necessary in metal steams such atomic bonds seem, to z. B. sodium steam exists to approximately 1% out well 2 - molecules. Metals arrange themselves rather to a metal lattice, in which the bonding electrons are distributed over the whole lattice, one speak also of an electron gas. In the electron gas arrange themselves positively charged atomic trunks. A more accurate view with consideration of the orbital model supplies the band model.

In connection with nonmetals the metals appear generally as cations , D. h. the outside electrons are transferred completely to the nonmetal atoms and it form an ionic compound (salt). At an ion lattice the ions are held together only by electrostatic forces.

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characteristics

from the kind of connection and the lattice structure result the following typical characteristics of the metals:

  • Opacity by easily adjustable electrons (by it that the electrons are not bound to certain energy levels (orbital), but freely in form of an electron gas, can they occur many wavelengths absorb and have therefore one grey to black color)
  • gloss, under easily adjustable electrons at the surface (by it that the electrons are not bound to certain energy levels (orbital), but freely in form of an electron gas to occur, can it the whole before taken up energy again emit. Thus the gloss develops)
  • for property ductility (ductility): In the metal lattice are transfers, which can move with a tension below the separation tension; depending upon type of lattice thus a metal deforms rather, it breaks
  • high melting point by the generally arranged binding forces
  • property electrical conductivity by easily adjustable electrons
  • property thermal conductivity by easily adjustable electrons
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to bloom and boiling temperatures

the following table shows the bloom and boiling temperatures of some metals (in °C with normal print):

Metal fusing temperature boiling temperature
aluminum 659 2467
tungsten 3390 5500
iron 1536 3070
magnesium 650 1120
copper 1083 2595
tin 231.9 2687
lead 327.4 1751
zinc 419.5 907

as high-melting one designates metal, their melting point T E over 2000K and/or. over the melting point of platinum (T E - platinum = 2045K = 1772°C) lies.

In addition the precious metals ruthenium , rhodium , osmium and iridium and metals of the groups of IVA (zirconium, hafnium ) belong, to VA (vanadium, niobium, tantalum), VIA (chrome, molybdenum, tungsten) and VIIA (technetium, rhenium).

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heat guidance characteristics

the characteristics such as density, thermal capacity, heat conductivity and thermal diffusivity, relevant for the thermal conduction , vary strongly. So for instance silver with 427 w (m K) has one approx. twenty-way higher heat conductivity than manganese. Further values.

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organization

traditional one divides metals after the density in heavy metals and light alloys and after reactivity into precious metals and unedle metals. See also for this the major item metallic material.

Besides straight for the chemical behavior the affiliation to main or Nebengruppen of the periodic system is crucial.

H He
left B C N O F Ne
well mg aluminium SI P S Cl acre
K approx. sports club Ti V CR Mn Fe CO never cu Zn Ga Ge As SE Br Kr
Rb SR Y Zr Nb Mo Tc Ru RH Pd AG CD in SN self-service of width unit I Xe
Cs Ba La * Hf TA W RH OS IR Pt outer Hg tl Pb Bi Po RK Rn
Fr RA AC ** Rf railways Sg Bh Hs Mt DS Rg
* Ce Pr lp Pm Sm European Union Gd Tb Dy Ho it TM Yb Lu
** Th Pa U NP Pu at the cm UC Cf it FM MD NO Lr


of light alloys < 5 g/cm ³ heavy metals < 10 g/cm ³ heavy metals > 10 g/cm ³

see also: Refraktärmetalle

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occurrence

the earth core consists mostly of iron, since it is the physically most stable element.

In the earth's crust against it the nonmetals outweigh, relatively frequent metals are aluminum, iron, manganese, titanium, calcium, magnesium, sodium and potassium. Many rare metals arise however in their dismantling places strongly enriched, so that a dismantling is worthwhile itself.

Rocks, which contain classical work metals in concentrations worthy of exploitation, are called ores. To the most important ores belong:

other metal connections such as common salt or lime are not designated against it than ores.

Some precious metals, v. A. Gold, also gediegen , D come. h. in pure form and not as connection/ore forwards.

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connections

the connections or also solutions of different metals are called alloys. These have often completely different physical and chemical characteristics than the pure metals. Above all the hardness is partly higher around orders of magnitude. Likewise often the corrosion resistance is clearly increased. Pure metals are practically not used, except conductions with the production, since pure metals possess the largest conductivity. Here unalloyed metals, above all copper and aluminum are used.

With many nonmetals ionic compounds are entered, whereby however straight with transition metals and with larger anions (like the sulfide - ion) all transition stages for atomic bond occur.

With nonmetals such as hydrogen, carbon and nitrogen also storage connections are formed, whereby the nonmetal atoms are in gaps of the metal lattice, without changing this substantially. These storage connections keep the typical metal characteristics like the electrical conductivity.

Metal cations, v. A. those the Nebengruppenmetalle, form with Basen (water, ammonia, halides, cyanide and. v. A.) complex connections, whose stability cannot be explained alone by the electrostatic attraction.

Metals in higher Oxidationsstufen form also complex anions, z. B. chrome tri oxide CrO 3 separates in caustic potash solution under education chromate - of the anion CrO 4 2: CrO 3 + 2 KOH -> K 2 CrO 4 + H 2 O

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use

many metals are important materials. Our modern world would be impossible without metals. Without reason phases of the mankind development are not called after the used materials Steinzeit , Bronzezeit , Eisenzeit.

The following list does not contain the most important metals and alloying constituents, connections.

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metal as civilization development characteristic

on the basis the manners of processing and use of metals important epochs of the Menscheitsgeschichte are differentiated.

Generally is this:

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of metals in the astronomy

in the astronomy designates metal each chemical element with an ordinal number more highly than helium. This distinction is meaningful, since hydrogen and helium as well as some traces of lithium are the only elements, which are present after the Big Bang in the universe. All further elements result then for example in stars from nuclear fusion or from Supernovae. The Metallizität of objects of space can be understood therefore as indicator for its stellar activity.

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metal in Chinese philosophy

metal marks an element of the traditional five-element teachings.

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see also

Wiktionary: Metal - word origin, synonyms and translations
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