CARBON%20AND%20ITS%20COMPOUNDS

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CARBON AND ITS COMPOUNDS
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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.

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Compounds of Carbon are Widely Distributed in
Nature

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

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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

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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

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Allotropes of Carbon

• In nature, pure carbon occur in two forms-
• Diamond
• Graphite

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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.

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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
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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.

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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

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Hydrocarbons

• Hydrocarbons are compounds of carbon and hydrogen.

The natural source of hydrocarbons is petroleum
(crude oil)
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The Simplest Hydrocarbon

• Methane CH4

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

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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
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Unsaturated Hydrocarbons

• Unsaturated hydrocarbons contain a double or
  triple bond between two carbon atoms.
• The one with double bond are called alkenes

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Alkenes
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Alkynes

• Unsaturated hydrocarbons which contain triple
  bond between two carbon atoms.