Arsenic (33)

Arsenic and its compounds are poisonous as any reader of "who-done-it" books knows. Upon heating arsenic and some minerals containing arsenic, it sublimes (transfers from the solid to the gaseous state, without passing through the liquid state).

•Name: Arsenic
•Symbol: As
•Atomic number: 33
•Atomic weight: 74.92160
•Standard state: solid at 298 K
•CAS Registry ID: 7440-38-2
•Group in periodic table: 15
•Group name: Pnictogen
•Period in periodic table: 4
•Block in periodic table: p-block
•Color: metallic grey
•Classification: Semi-metallic

Historical information

Arsenic was discovered by Known since ancient times at no data in not known. Origin of name is from the Greek word "arsenikon" meaning "yellow orpiment". Arsenic compounds were mined by the early Chinese, Greek and Egyptian civilizations. No doubt they discovered its toxic properties early on.

It is believed that Albertus Magnus obtained the element in 1250 A.D. who obtained it by heating soap together with orpiment (arsenic trisulphide, As2S3).

Arsenic is one of the elements which has an alchemical symbol (alchemy is an ancient pursuit concerned with, for instance the transformation of other metals into gold), which is two circles joined by a line.

Physical properties

•Melting point: 1090 [or 817 °C (1503 °F)] (under pressure) K
•Boiling point: 887 [or 614 °C (1137 °F)] (sublimes) K
•Density of solid: 5727 kg m-3

Orbital properties

•Ground state electron configuration: [Ar].3d10.4s2.4p3
•Shell structure: 2.8.18.5
•Term symbol: 4S3/2

Isolation

It is not usually necessary to make arsenic in the laboratory as it is commercially available. Arsenic is found in nature in a number of minerals including realgar (As4S4), orpiment (As2S3), arsenolite (As2O3), and iron minerals such as arsenopyrite (FeAsS) and loellingite (FeAs2). Arsenic is made on an industrial scale by heating appropriate minerals in the absence of air. The arsenic is condensed out as a solid.

FeAsS (700°C) → FeS + As(g) → As(s)

Interesting Facts about Arsenic:

•Arsenic (English/French) Arsen (German) Arsenico (Italian) Arsénico (Spanish) Arsenik (Swedish)

•Arsenic is found naturally in a common mineral called Arsenopyrite or Mispickel (FeSAs). It is also found in arsenides of metals such as silver, cobalt and nickel. Apart from these inorganic forms, arsenic is found in food, water and air also.

•Arsenic is located in the Groups 13,14,15,16 and 17 of the Periodic Table and hence, is classified as a metalloid element. Thus, it has the properties of both metals and non-metals.

•The most common grey arsenic has a metallic sheen and conducts electricity. Yellow arsenic is metastable, a poor electrical conductor and does not have a metallic sheen. Black arsenic is glassy, brittle and a poor electrical conductor.

•Due to its high level of toxicity, arsenic has been named as the ‘Kings of Poison’. Hence, for the same reason, it is used as a wood preservative against insects, bacteria and fungi. It also finds its use in making insecticides, poison, weed killers, etc.

•Arsenic, in the form of Gallium arsenide, is used in lasers that are employed to convert electricity into coherent light.

•Arsenic is used in ammunition manufacturing, since it helps to create harder and rounder bullets.

•The top producers of arsenic are China, Peru, Chile and Morocco. While the production from Peru comes from copper mining, production in China comes from mining of gold.

•Pure arsenic is less dangerous than arsenic compounds, such as AsH3 and As2O3, which are absorbed easily and are carcinogenic with high toxicity.

•In the 18th, 19th and 20th century, arsenic was used in the form of medicines, two most common being arsphenamine and arsenic trioxide. While the former medication was prescribed for syphilis and trypanosomiasis, the latter one was useful in treating cancer.

•Some of the side effects of arsenic include agitation, constipation, darkening of skin, drowsiness, earache, poor appetite, increased sweating, mouth sores, fatigue, weight loss, nausea, nose bleeding, vomiting, depression, seizures, tremors, dry eyes, allergic reactions, sudden weight gain, wheezing, irregular pulse and increased thirst.

Gallium (31)

Gallium is the only metal, except for mercury, cesium, and rubidium, which can be liquid near room temperatures; this makes possible its use in high-temperature thermometers. It has one of the longest liquid ranges of any metal and has a low vapor pressure even at high temperatures.

Ultra-pure gallium has a beautiful, silvery appearance, and the solid metal exhibits a conchoidal fracture similar to glass. The metal expands on solidifying; therefore, it should not be stored in glass or metal containers, as they may break as the metal solidifies.

•Name: Gallium
•Symbol: Ga
•Atomic number: 31
•Atomic weight: 69.723 
•Standard state: solid at 298 K (but melts only slightly above this temperature)
•CAS Registry ID: 7440-55-3
•Group in periodic table: 13
•Period in periodic table: 4
•Block in periodic table: p-block
•Color: silvery white
•Classification: Metallic

Historical information

Gallium was discovered by Paul-Emile Lecoq de Boisbaudran at 1875 in France. Origin of name is from the Latin word "Gallia" meaning "France" and perhaps also from the Latin word "gallus" (the cock, a translation of Lecoq, the discoveror of gallium). Gallium was an element whose existence was predicted by Mendeleev in 1871. He predicted that the then unknown element gallium should resemble aluminum in its properties. He suggested therefore the name eka-aluminium (symbol Ea). His predictions for the properties of gallium are remarkably close to the reality. Gallium was discovered spectroscopically by Paul-Emile Lecoq de Boisbaudran in 1875, who in the same year obtained the free metal by electrolysis of a solution of the hydroxide Ga(OH)3 in KOH.

Physical properties

•Melting point: 302.91 [or 29.76 °C (85.57 °F)] K
•Boiling point: 2477 [or 2204 °C (3999 °F)] K

Orbital properties

•Ground state electron configuration: [Ar].3d10.4s2.4p1
•Shell structure: 2.8.18.3
•Term symbol: 2P1/2

Isolation

Gallium is normally a byproduct of the manufacture of aluminum. The purification of bauxite by the Bayer process results in concentration of gallium in the alkaline solutions from an aluminum:gallum ratio from 5000 to 300. Electrolysis using a mercury electrode gives a further concentration and further electrolysis using a stainless steel cathode of the resulting sodium gallate affords liquid gallium metal.

Very pure gallium requires a number of further processes ending with zone refining to make very pure gallium metal.

Interesting Facts:

Gallium (English, French, German, Swedish) Gallio (Italian) Galio (Spanish)

Low melting gallium alloys are used in some medical thermometers as non-toxic substitutes for mercury.

Gallium arsenide is used in semiconductor production mainly for laser diodes, light-emitting diodes and solar panels. It is also used to create brilliant mirrors.

Gallium has the second largest liquid range of any element and is one of the few metals that is liquid near room temperature (m.pt. 29.76 oC, 85.6 oF ), melting in the hand.

The other metals with this property are cesium, francium and mercury.

Bromine is the only non-metallic element that is liquid at or around room-temperature.

Gallium liquid clings to or wets glass and similar surfaces.

Gallium also has the unusual property that (like water) it expands as it freezes.

Four other elements expand when they freeze: silicon, bismuth, antimony and germanium

29^th:
GERMANIUM (32)

Germanium is a gray-white semi-metal, and in its pure state is crystalline and brittle, retaining its luster in air at room temperature. It is a very important semiconductor material. Zone-refining techniques have led to production of crystalline germanium for semiconductor use with an impurity of only one part in 10-10.

Certain germanium compounds have a low mammalian toxicity, but a clear activity against certain bacteria, which makes them of interest as chemotherapeutic agents.

•Name: Germanium
•Symbol: Ge
•Atomic number: 32
•Atomic weight: 72.64
•Standard state: solid at 298 K
•CAS Registry ID: 7440-56-4
•Group in periodic table: 14
•Period in periodic table: 4
•Block in periodic table: p-block
•Color: greyish white
•Classification: Semi-metallic

Historical information

Germanium was discovered by Clemens Winkler at 1886 in Germany. Origin of name is from the Latin word "Germania" meaning "Germany". Germanium was an element whose existence was predicted by Mendeleev in 1871. He predicted that the then unknown element germanium should resemble silicon in its properties. He suggested therefore the name ekasilicon (symbol Es). His predictions for the properties of germanium are remarkably close to the reality. Germanium was discovered in a mineral called argyrodite by Clemens Alexander Winkler in 1886.

Physical properties

•Melting point: 1211.4 [or 938.3 °C (1720.9 °F)] K
•Boiling point: 3093 [or 2820 °C (5108 °F)] K
•Density of solid: 5323 kg m-3

Orbital properties

•Ground state electron configuration: [Ar].3d10.4s2.4p2
•Shell structure: 2.8.18.4
•Term symbol: 3P0

Isolation

There is normally no need to make germanium in the laboratory as it is readily available commercially. Germanium is available through the treatment of germanium dioxide, GeO2, with carbon or hydrogen. The extraction of germanium from flue dust is complex because of the difficulty in separating it from zinc, which is also present.

GeO2 + 2C → Ge + 2CO

GeO2 + 2H2 → Ge + 2H2O

Very pure germanium can be made by the reaction of GeCl4 with hydrogen.

GeCl4 + 2H2 → Ge + 4HCl

Interesting Facts about Germanium:

Germanium (English, French, German, Swedish)  Germanio (Italian/Spanish)

Trace impurities can be added to germanium to produce semiconductors.

Germanium and germanium oxide are transparent to infrared light and exhibit other desirable optical properties, so the element is used in infrared spectrometers and lenses.

Elemental arsenic occurs in two solid modifications: yellow, and grey or metallic, with specific gravities of 1.97, and 5.73, respectively. The element is a steel grey, very brittle, crystalline, semi metallic (metalloid) solid. It tarnishes in air, and when heated rapidly oxidizes to arsenous oxide which has a garlic odor.

Zinc (30)

Zinc-deficient animals require 50% more food to gain the same weight of an animal supplied with adequate amounts of zinc. Zinc is not particularly toxic and is an essential element in the growth of all animals and plants.

Plating thin layers of zinc on to iron or steel is known as galvanizing and helps to protect the iron from corrosion.

•Name: Zinc
•Symbol: Zn
•Atomic number: 30
•Atomic weight: 65.38
•Standard state: solid at 298 K
•CAS Registry ID: 7440-66-6
•Group in periodic table: 12
•Period in periodic table: 4
•Block in periodic table: d-block
•Color: bluish pale grey
•Classification: Metallic

Historical information

Zinc was discovered by Andreas Marggraf at 1746 in Germany. Origin of name is from the German word "zink". Centuries before zinc was recognized as a distinct element, zinc ores were used for making brass (a mixture of copper and zinc). A brass dating from between 1400-1000 BC has been found in Palestine. An alloy containing 87% zinc was found in prehistoric ruins in Transylvania. The smelting of zinc ores with copper was apparently discovered in Cyprus and was used later by the Romans. Metallic zinc was produced in the 13th century in India by reducing calamine (zinc carbonate, ZnCO3) with organic substances such as wool.

The metal was rediscovered later in Europe. William Champion set up a zinc industry in Bristol (England) in the 1740s. Other plants were established a little later in Belgium and Silesia.

Sometime prior to the autumn of 1803, the Englishman John Dalton was able to explain the results of some of his studies by assuming that matter is composed of atoms and that all samples of any given compound consist of the same combination of these atoms. Dalton also noted that in series of compounds, the ratios of the masses of the second element that combine with a given weight of the first element can be reduced to small whole numbers (the law of multiple proportions). This was further evidence for atoms. Dalton's theory of atoms was published by Thomas Thomson in the 3rd edition of his System of Chemistry in 1807 and in a paper about strontium oxalates published in the Philosophical Transactions. Dalton published these ideas himself in the following year in the New System of Chemical Philosophy. The symbol used by Dalton for zinc is a circle with a capital 'Z' inside.

Physical properties

•Melting point: 692.68 [or 419.53 °C (787.15 °F)] K
•Boiling point: 1180 [or 907 °C (1665 °F)] K
•Density of solid: 7140 kg m-3

Orbital properties

•Ground state electron configuration: [Ar].3d10.4s2
•Shell structure: 2.8.18.2
•Term symbol: 1S0

Isolation

Zinc metal is readily available commercially so it is not normally necessary to make it in the laboratory. Most zinc production is based upon sulfide ores. These are roasted in industrial plants to form zinc oxide, ZnO. This may be reduced with carbon to form zinc metal, but in practice ingenious technology is required to ensure that the resulting zinc does not contain oxide impurities.

ZnO + C → Zn + CO

ZnO + CO → Zn + CO2

CO2 + C → 2CO

The other type of extraction is electrolytic. Dissolution of crude zinc oxide, ZnO, in sulphuric acid gives zinc sulphate, ZnSO4 in solution. Cadmium is an impurity and this is removed as a precipitate of cadmium sulphate by the addition of zinc dust. Electrolysis of the ZnSO4 solution using aluminum cathodes and lead alloyed with silver anodes gives pure zinc metal coated on the aluminum. Oxygen gas is liberated at the anode.

Very pure zinc may be formed from crude zinc by zone refining and single crystals can be grown with purities of better than 99.9999%.

Interesting Facts:

1. Zinc (English) Zinc (French) Zink (Deutsch) Zinco (Italian/Spanish) Zink (Swedish)

2. Zinc's use has been traced back over 2500 years. The earliest documented use was in ancient ornaments and decorations found in eastern countries. Alchemists also produced zinc oxide, which they called “philosophers wool.”

3. Over fifty countries produce zinc, the largest being China, which tops 3,500,000 tons per year! A majority of zinc mined comes from underground sources in the form of zinc ore. After being mined, it must undergo processing as it isn't pure enough to be smelted.

4. Most zinc produced is used in galvanizing. This process is usually used to protect iron or steel from corrosion. Its properties make it more reactive than surrounding metals, meaning the corrosion (usually rust) is attracted to the zinc. This makes the metals much more durable in harsh environments, reducing the need for periodic replacement.

5. Brass alloy contains 3% to 45% zinc, with the remainder being copper. Brass is used to form many common items such as: musical instruments, decorations, building hardware, and tools. Other common zinc alloys include nickel silver, electrical solder, and a lead substitute in water pipes.

6. Zinc can help you stay young! It is believed to have anti-oxidant properties, which keep our skin and muscles from aging. It is available in dietary supplements, as well as in many natural foods. There is also a belief that zinc can help to shorten the length of the common cold as a homeopathic treatment.

7. Although zinc is helpful in moderation, an excess is dangerous both to humans and to the environment. It can reduce the rate our bodies absorb copper and iron, and inhalation has shown to cause a symptom called the “zinc shakes”. Processing facilities have also been shown to increase the heavy metal content in bodies of water. Additionally, high zinc levels in the soil can rob plants of the ability to absorb nutrients.

8. Back to science. Zinc's atomic number is 30, meaning an atom has thirty protons in the nucleus. Its atomic weight is 35.38, and has a melting point of 787.1 degrees Fahrenheit. It has a shiny bluish-white color in its pure form and is hard and brittle.

9. Zinc can only be created by nuclear fusion from supernovas. When massive stars reach the end of their life, they can explode and erupt their contents into space. This is the primary source of most heavy elements in the universe.

Copper (29)

Copper is one of the most important metals. Copper is reddish with a bright metallic luster. It is malleable, ductile, and a good conductor of heat and electricity (second only to silver in electrical conductivity). Its alloys, brass and bronze, are very important. Monel and gun metals also contain copper. Apparently the reason that policemen in the USA are nicknamed "cops" or "coppers" is to do with their uniforms which used to have copper buttons.

The most important compounds are the oxide and the sulphate, (blue vitriol).

•Name: Copper
•Symbol: Cu
•Atomic number: 29
•Atomic weight: 63.546
•Standard state: solid at 298 K
•CAS Registry ID: 7440-50-8
•Group in periodic table: 11
•Group name: Coinage metal
•Period in periodic table: 4
•Block in periodic table: d-block
•Color: copper, metallic
•Classification: Metallic

Historical information

Copper was discovered by Known since ancient times at no data in not known. Origin of name is from the Latin word "cuprum" meaning the island of "Cyprus". The discovery of copper dates from prehistoric times. There are reports of copper beads dating back to 9000BC found in Iraq. Methods for refining copper from its ores were discovered around 5000BC and a 1000 or so years later it was being used in pottery in North Africa.

Part of the reason for it being used so early is simply that it is relatively easy to shape. However it is somewhat too soft for many tools and around 5000 years ago it was discovered that when copper is mixed with other metals the resulting alloys are harder than the copper itself. As examples, brass is a mixture of copper and zinc while bronze is a mixture of copper and tin.

Copper is one of the elements which has an alchemical symbol, what looks like the symbol for female.

Sometime prior to the autumn of 1803, the Englishman John Dalton was able to explain the results of some of his studies by assuming that matter is composed of atoms and that all samples of any given compound consist of the same combination of these atoms. Dalton also noted that in series of compounds, the ratios of the masses of the second element that combine with a given weight of the first element can be reduced to small whole numbers (the law of multiple proportions). This was further evidence for atoms. Dalton's theory of atoms was published by Thomas Thomson in the 3rd edition of his System of Chemistry in 1807 and in a paper about strontium oxalates published in the Philosophical Transactions. Dalton published these ideas himself in the following year in the New System of Chemical Philosophy.

Physical properties

•Melting point: 1357.77 [or 1084.62 °C (1984.32 °F)] K
•Boiling point: 3200 [or 2927 °C (5301 °F)] K
•Density of solid: 8920 kg m-3

Orbital properties

•Ground state electron configuration: [Ar].3d10.4s1
•Shell structure: 2.8.18.1
•Term symbol: 2S1/2

Isolation

Copper metal is readily available commercially so it is not normally necessary to make it in the laboratory. Most copper production is based upon sulfide ores containing little copper but quite a lot of iron. New cleaner technologies are now important but older processes present major environmental problems. Complex procedures are used initially to form a form of copper sulfide appropriate for final reduction via a copper(I) oxide. The resulting crude copper is purified using an electrolytic procedure involving plating onto pure copper cathodes.

2Cu2S + 3O2 → 2Cu2O + 2SO2

2Cu2O + Cu2S → 6Cu + SO2

Notably, the purification step leaves an "anode slime" which contains useful amounts of silver and gold.

Nickel (28)

Nickel is found as a constituent in most meteorites and often serves as one of the criteria for distinguishing a meteorite from other minerals. Iron meteorites, or siderites, may contain iron alloyed with from 5 to nearly 20% nickel. The USA 5-cent coin (whose nickname is "nickel") contains just 25% nickel. Nickel is a silvery white metal that takes on a high polish. It is hard, malleable, ductile, somewhat ferromagnetic, and a fair conductor of heat and electricity.

Nickel carbonyl, [Ni(CO)4], is an extremely toxic gas and exposure should not exceed 0.007 mg M-3.

•Name: Nickel
•Symbol: Ni
•Atomic number: 28
•Atomic weight: 58.6934
•Standard state: solid at 298 K
•CAS Registry ID: 7440-02-0
•Group in periodic table: 10
•Period in periodic table: 4
•Block in periodic table: d-block
•Color: lustrous, metallic, silvery tinge
•Classification: Metallic

Historical information

Nickel was discovered by Axel Fredrik Cronstedt at 1751 in Sweden. Origin of name is from the German word "kupfernickel" meaning Devil's copper or St Nicholas's (Old Nick's) copper. Minerals containing nickel were of value for coloring glass green. The mineral used for coloring glass was called kupfernickel (false copper). Nickel was discovered by Baron Axel Frederik Cronstedt in 1751 in a mineral called niccolite. Apparently, he had expected to extract copper from this mineral but got none at all, obtaining instead a white metal that he called nickel after the mineral from which it was extracted.

Physical properties

•Melting point: 1728 [or 1455 °C (2651 °F)] K
•Boiling point: 3186 [or 2913 °C (5275 °F)] K
•Density of solid: 8908 kg m-3

Orbital properties

•Ground state electron configuration: [Ar].3d8.4s2
•Shell structure: 2.8.16.2
•Term symbol: 3F4

Isolation

It is not normally necessary to make nickel in the laboratory as it is available readily commercially. Small amounts of pure nickel can be isolated in the laboratory through the purification of crude nickel with carbon monoxide. The intermediate in this process is the highly toxic nickel tetracarbonyl, Ni(CO)4. The carbonyl decomposes on heating to about 250°C to form pure nickel powder.

Ni + 4CO (50°C) → Ni(CO)4 (230°C) → Ni + 4CO

The Ni(CO)4 is a volatile complex which is easily flushed from the reaction vessel as a gas leaving the impurities behind. Industrially, the Mond process uses the same chemistry. Nickel oxides are reacted with "water gas", a mixture of CO + H2). Reduction of the oxide with the hydrogen results in impure nickel. This reacts with the CO component of the water gas to make Ni(CO)4 as above. Thermal decomposition leaves pure nickel metal.

Nickel (English) Nickel (French) Nickel (Deutsch) Nichel (Italian) Niquel (Spanish) Nickel (Swedish)

Interesting Facts:

Nickel is ferromagnetic at room temperature, just like its close periodic table neighbors iron and cobalt.

Nickel is 100 times more concentrated below Earth’s crust than in it. Nickel is believed to be the second most abundant element in the earth’s core, with iron most abundant by a large margin.

Nickel is the main metal in Mu-metal, which has the fascinating property of magnetic shielding. Magnets will normally attract metals such as iron. If you place Mu-metal between magnet and metal, the attraction disappears. This is because very little magnetic field is transmitted through Mu-metal. Mu-metal is approximately 80% nickel, 20% iron with a little molybdenum. (5)

The strange properties of nickel’s alloys don’t end with Mu-metal. Nitinol is a nickel alloy, discovered in the 1960s, that remembers its previous shape. Heat this 1:1 nickel-titanium alloy to about 500 oC, and bend it into whatever shape you like; you could bend a wire to make your name. Then cool it and bend the wire into a spring. Heat the wire again and, remarkably, the spring disappears, and the first shape – in this case your name – returns.

Nickel is corrosion resistant – it is one of the elements used in stainless steel. The presence of nickel in meteorite metal means it would have stayed bright and shiny in the hands of ancient people for much longer than if nickel had been absent.

Until the invention of rare-earth magnets, such as neodymium-iron-boron, the strongest permanent magnets – Alnico magnets – were made from a nickel alloy: mainly aluminum, nickel, cobalt and iron. Unusually, Alnico magnets retain their magnetism even when heated until they glow red hot.

Supernova 2007bi was observed in 2007. One of the products of this supernova was nickel-56, synthesized during the explosion. Nickel of mass three times greater than our entire sun was made. Nickel-56 is radioactive, decaying to cobalt-56, which itself decays to stable iron-56