Important Elements and Compounds

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It is Colourless, Odourless, Tasteless, Inflammable and Lightest known substance (gas).

It is found in water (H2O), in organic compounds and all living things. It is neutral to litmus.

Can be produced in the laboratory by Bosch process and by electrolysis. It is used m balloons, ships, for ammonia and vanaspati ghee preparation etc.


It is Colourless, Tasteless, Odourless, Combustible Slightly Heavier than Air, some what soluble in Water. Atmospheric Air contains Oxygen by about 21% by Weight.

It can be prepared in the laboratory but also in factories on Commercial Scale.

It can be liquefied and solidified. It is employed in welding process and also used in hospitals for artificial respiration.


It is colourless, tasteless, odourless, non – combustible, in – active, non – poisonous gas, forming about 80% of the atmospheric air by volume and 75% by weight.

It is slightly lighter than air and only slightly soluble in water. It is used for filling electric bulbs, for making fertilizers, ammonia, nitrates etc.

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It is an allotropic form of oxygen containing three atoms in the molecule and is formed when oxygen or air is subjected to silent electric charge.

It is bluish gas, very active chemically and a powerful oxidizing agent. It is found in the upper atmosphere some 25 to 30 km from the earth’s surface, called ozonosphere layer.

It is this layer which absorbs a large proportion of the sun’s ultraviolet radiation. Ozone is used for purifying air and water and in bleaching.


It is universal constituent of living matter. It can be mainly classified into two forms :

Allotropic form and amorphous form.

Diamond and graphite are two of its allotropic forms whereas charcoal, lamp black, coke etc., belong to amorphous form. Carbon atoms are capable of uniting with each other to form very large molecules upon which life is based.


It is a very costly stone and hardest naturally occurring substance. It is transparent to X – Rays only. It is used for jewellery, drilling and cutting tools. It can be cut only by a diamond.

Graphite :

It is soft, easily powdered and gives a greasy feeling. It is good conductor of heat and electricity.

Used for lead pencils, electrical machines and as lubricant for heavy machines. Also used as a moderator in nuclear reactors.


Over long periods of time, trees, bones get buried under the ground by violent geological changes. As a result of chemical reaction with clay, sand, water etc. these get transformed to coal in nature.

This process is known as carbonization. Due to this process we get substances like peat, lignite, bituminous (soft) and anthracite (hard) depending upon degree of carbonization.

Organic compounds

Constitute substances like petroleum, coal, food components (protein, fats carbohydrates, vitamins), anaesthetics, antiseptic, antibiotics, cotton, wool, silk synthetic fibres.


These are compounds of hydrogen and carbon vizard methane, ethane, propane, butane benzene. Hydrocarbons are found abundantly in nature viz., petroleum, natural gas coal etc.

From these natural hydrocarbons or parent organic compounds many other organic compounds can be derived.


It is a hydrocarbon compound extracted from the ground or sea bed by deep drilling, Petroleum is then refined in distilleries and converted into petroleum products such as petrol, diesel, grease, lubricating oil.

The residue of this is used for making man – made fibre like nylon, terylene, plastic etc., and wide range of drugs.

Natural gas, CNG are another range of products of hydrocarbon compounds.

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