CARBON AND ITS COMPOUNDS

CARBON AND ITS COMPOUNDS


CARBON






Carbon belongs to the group IV of
the periodic table.
It has four electrons in its
outermost orbit, so its valency is
four.
Carbon is a non-metal.


Compounds of Carbon are Widely
Distributed in Nature


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


Why so many Carbon Compounds
in nature?


Because carbon is
chemically unique.



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


Carbon- Long Chains


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


Allotropes of Carbon





In nature, pure carbon occur in two
formsDiamond

Graphite


What are Allotropes ?


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



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


Physical Properties of
Diamond and Graphite
Property

Diamond

Graphite

Appearance

Transparent

Black, Shiny

Hardness

Very Hard

Soft, slippery to
touch

Thermal
Conductivity

Very poor

moderate

Electrical
Conductivity

Poor

Good conductor

Density(kg/m3)

3510

2250

Uses

Jewellery, drilling

Dry cell, electric
arc, lubricant,
pencil lead


How Diamond and Graphite are
chemically identical?


These results of thes experiments answer this question:



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



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


Why the physical properties of diamond
and graphite are so different?


Due to the difference in the arrangement
of carbon atoms in diamond and graphite

Hydrocarbons


Hydrocarbons are compounds of carbon
and hydrogen.

The natural source of
hydrocarbons is
petroleum (crude oil)


The Simplest Hydrocarbon
Methane CH4
A
molecule
of
methane has four
hydrogen
atoms
linked to one central
atom of carbon.


S
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H
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A
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a
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Alkanes


The hydrocarbons methane, ethane

propane and butane form a series of
carbon compounds known as alkanes



The alkane series can be represented by
the general formula


Isomerism


Compounds having the same molecular formulae
but different structural arrangement of atoms in
them are known as isomers, and the
phenomenon is known as isomerism
Isomers of Butane –
Obtained by rearranging
the carbon and the
hydrogen atoms


Unsaturated Hydrocarbons




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

The one with double bond are called
alkenes


Alkenes


Alkynes


Unsaturated hydrocarbons which contain
triple bond between two carbon atoms.