Important Elements and Compounds

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Alkalies

Bases soluble in water are called alkalies viz. sodium hydroxide and potassium hydroxide.

They have a soapy touch, bitter taste and turn red litmus blue and yellow turmeric powder (Haldi) brown.

Uranium

Its main ore is pitchblende. It is a radioactive metal, occurring in nature, comprising of 99.28% (92238U) and 71% (92235U).

The isotope (92238U) has the capacity of sustaining a nuclear chain reaction and is used in nuclear reactors and nuclear weapons.

Thorium

It is a dark grey radio active metal used in alloys and as a source of nuclear energy. Its compounds occur in monozite and thorite

Plutonium

It is a transuranic element (element having atomic number more than 92) which do not occur in nature but may be obtained by nuclear reaction. It is radio active.

The isotope (94239Pu) is produced in nuclear reactors and is of great importance as it undergoes nuclear fission when bombarded by slow neutrons. This isotope is employed in nuclear weapons.

Iron

It is extracted from its ores by the blast furnace process.

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Iron obtained from blast furnace is called pig iron or cast iron containing about 5% carbon.

Pure iron is called wrought iron which does not contain carbon more than 0.2%, or any other impurities or constituents.

Wrought iron is soft, malleable, easy to work on.

It is used for making chains, wires, furniture, items of decoration and electromagnets.

Copper

It is a metal element, malleable, ductile and best conductor of electricity after silver.

It is widely used for making electrical wires and in steam boilers being not affected by water or steam.

It is used for alloying e.g., bronze, brass, gun metal, German silver, bell metal, Dutch metal etc.

Zinc

It is a metal element, bluish white in colour. It occurs as calamine, zincite and zinc blende.

It is used for alloying e.g., brass and in galvanizing iron.

Aluminium

It is a metal element, light white in colour, occurring widely in nature in clays, extracted mainly from ore: bauxite.

It is ductile, malleable, can be drawn into wire, widely used in electric transmission and distribution, being a good conductor of electricity.

It is quite light. It is also used as an alloy.

Alloyed aluminium is extensively used in manufacturing utensils, electrical apparatus, automobile engines, pistons and also in aircrafts.

Silver

It is a metal element, soft, white malleable, best conductor of electricity.

It is used in jewellery and coins. Its compounds are used in photography.

Gold

It is a metal element, bright yellow, soft, malleable, non – corrodible by air and unaffected by most acids, but dissolves in aqua regia.

It is alloyed with silver and copper. It is the best conductor of electricity but is not used being very costly.

Gold, particularly in India is extensively used for jewellery and dentistry.

Its compounds are employed in photography and medicines. It is also used for surface plating.

Potassium

It is a metal used extensively in the form of various salts which are further used as fertilizers.

It is necessary for life and is found in all living matter.

Calcium

It occurs in nature in the form of calcium sulphate (gypsum) and calcium carbonate (lime stone, marble and chalk).

Calcium is an essential constituent of bones and teeth. Some of its compounds are used in industry.

Magnesium

It occurs as magnesite, dolomite, carnallite as well as in many compounds.

Its compounds are used in medicine.

It is used in light weight alloys, in photography and incendiary bombs.

It is essential to life also as it occurs in chlorophyll.

Mercury

It is a silver white, liquid form metal, widely used in thermometers, barometers, manometers and many scientific apparatus.

Its compounds are poisonous and are used in medicines. It is a very heavy metal. Its specific gravity is 13.6.

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