CARBON AND ITS CARBON AND ITS COMPOUNDSCOMPOUNDS

CARBONCARBON Carbon belongs to the group Carbon belongs to the group

IV of the periodic table.IV of the periodic table. It has four electrons in its It has four electrons in its

outermost orbit, so its outermost orbit, so its valency is four.valency is four.

Carbon is a non-metal.Carbon is a non-metal.

Compounds of Carbon are Compounds of Carbon are Widely Distributed in NatureWidely Distributed in Nature

The number of carbon compounds is The number of carbon compounds is larger than that of all other elements larger than that of all other elements put together.put together.

Why so many Carbon Why so many Carbon Compounds in nature?Compounds in nature?

Because carbon is Because carbon is chemically unique.chemically unique.

Only carbon atoms Only carbon atoms have the ability to have the ability to combine with combine with themselves to themselves to form long chainsform long chains

Carbon- Long ChainsCarbon- Long Chains

A long chain, in turn, provides a A long chain, in turn, provides a convenient backbone of atoms to convenient backbone of atoms to which other atoms can attach which other atoms can attach themselves in a variety of waysthemselves in a variety of ways

Allotropes of CarbonAllotropes of Carbon

In nature, pure carbon occur in two In nature, pure carbon occur in two forms-forms-

DiamondDiamond GraphiteGraphite

What are Allotropes ?What are Allotropes ?

Allotropes are elements which are Allotropes are elements which are chemically identical, but they differ chemically identical, but they differ markedly in their physical properties.markedly in their physical properties.

Diamond and Graphite – two Diamond and Graphite – two allotropes of carbon differ in their allotropes of carbon differ in their physical properties.physical properties.

Physical Properties of Physical Properties of Diamond and GraphiteDiamond and Graphite

PropertyProperty DiamondDiamond GraphiteGraphiteAppearanceAppearance TransparentTransparent Black, ShinyBlack, Shiny

HardnessHardness Very HardVery Hard Soft, slippery to Soft, slippery to touchtouch

Thermal Thermal ConductivityConductivity

Very poorVery poor moderatemoderate

Electrical Electrical ConductivityConductivity

PoorPoor Good conductorGood conductor

Density(kg/m3)Density(kg/m3) 35103510 22502250

UsesUses Jewellery, Jewellery, drillingdrilling

Dry cell, Dry cell, electric arc, electric arc, lubricant, pencil lubricant, pencil leadlead

How Diamond and Graphite are How Diamond and Graphite are chemically identical?chemically identical?

These results of thes experiments answer this These results of thes experiments answer this question:question:

On heating diamond or graphite in the air, they On heating diamond or graphite in the air, they burn completely to form carbon dioxide.burn completely to form carbon dioxide.

Equal quantities of diamond and graphite when Equal quantities of diamond and graphite when burned, produce exactly the same amount of burned, produce exactly the same amount of carbon dioxide. carbon dioxide.

Why the physical properties of Why the physical properties of diamond and graphite are so diamond and graphite are so

different?different? Due to the difference in the Due to the difference in the

arrangement of carbon atoms in arrangement of carbon atoms in diamond and graphitediamond and graphite

HydrocarbonsHydrocarbons

Hydrocarbons are compounds of Hydrocarbons are compounds of carbon and hydrogen.carbon and hydrogen.

The natural source of

hydrocarbons is

petroleum (crude oil)

The Simplest HydrocarbonThe Simplest Hydrocarbon

Methane CHMethane CH44

A molecule of methane has four hydrogen atoms linked to one central atom of carbon.

HHyyddrrooccaarrbboonnss

Saturated

Alkanes

AlkanesAlkanes

The hydrocarbons methane, ethane The hydrocarbons methane, ethane propane and butane form a series of propane and butane form a series of carbon compounds known as alkanescarbon compounds known as alkanes

The alkane series can be represented The alkane series can be represented by the general formula by the general formula

IsomerismIsomerism Compounds having the same molecular Compounds having the same molecular

formulae but different structural formulae but different structural arrangement of atoms in them are known arrangement of atoms in them are known as isomers, and the phenomenon is known as isomers, and the phenomenon is known as isomerismas isomerismIsomers of Butane – Obtained by rearranging the carbon and the hydrogen atoms

Unsaturated HydrocarbonsUnsaturated Hydrocarbons

Unsaturated hydrocarbons contain a Unsaturated hydrocarbons contain a double or triple bond between two double or triple bond between two carbon atoms. carbon atoms.

The one with double bond are called The one with double bond are called alkenesalkenes

AlkenesAlkenes

AlkynesAlkynes Unsaturated hydrocarbons which Unsaturated hydrocarbons which

contain triple bond between two contain triple bond between two carbon atoms.carbon atoms.