CHAPTER – 4
CARBON AND ITS COMPOUNDS
q Carbon is a versatile element.
q In earth’s crust, carbon is 0.02% and found in form of minerals.
q Atmosphere has 0.03% of Carbon dioxide.
q All living structures are carbon based.
Covalent Bond in Carbon
– The atomic number of carbon is 6 and its electronic configuration is 2, 4. To
attain a noble gas configuration it can
1. Gain 4 electrons. But it would be difficult for nucleus to hold 4 extra electrons.
2. Lose 4 electrons. But it would require a large amount of energy to remove
4 electrons.
– It is difficult thus for an atom of carbon to either gain or lose electrons.
– Carbon attains the noble gas configuration by sharing its valence electrons
with other atoms. Atoms of other elements like hydrogen, oxygen, nitrogen,
chlorine also show sharing of valence electrons.
– Formation of H2, O2 and N2 is shown as below :
31 X – Science
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, – It is evident that the number of shared pair of electrons can be one, two or
three. Try making the structures of H2O and CH4.
– Bond formed by the sharing of an electron pair between two atoms is called
covalent bond.
– Covalently bonded molecules have low melting and boiling points because of
comparatively weaker intermolecular forces, unlike ionic compounds.
– These molecules are generally poor conductor of electricity since no charged
particles are formed.
Versatile Nature of Carbon Atoms:
Two important properties of carbon atom enable carbon to form enormously large
number of compounds.
CATENATION : property of carbon atom to form bond with other atoms of
carbon is called catenation. Like carbon, silicon forms compounds with hydrogen
upto seven or eight atoms of silicon.
32 X – Science
AK
CARBON AND ITS COMPOUNDS
q Carbon is a versatile element.
q In earth’s crust, carbon is 0.02% and found in form of minerals.
q Atmosphere has 0.03% of Carbon dioxide.
q All living structures are carbon based.
Covalent Bond in Carbon
– The atomic number of carbon is 6 and its electronic configuration is 2, 4. To
attain a noble gas configuration it can
1. Gain 4 electrons. But it would be difficult for nucleus to hold 4 extra electrons.
2. Lose 4 electrons. But it would require a large amount of energy to remove
4 electrons.
– It is difficult thus for an atom of carbon to either gain or lose electrons.
– Carbon attains the noble gas configuration by sharing its valence electrons
with other atoms. Atoms of other elements like hydrogen, oxygen, nitrogen,
chlorine also show sharing of valence electrons.
– Formation of H2, O2 and N2 is shown as below :
31 X – Science
AK
, – It is evident that the number of shared pair of electrons can be one, two or
three. Try making the structures of H2O and CH4.
– Bond formed by the sharing of an electron pair between two atoms is called
covalent bond.
– Covalently bonded molecules have low melting and boiling points because of
comparatively weaker intermolecular forces, unlike ionic compounds.
– These molecules are generally poor conductor of electricity since no charged
particles are formed.
Versatile Nature of Carbon Atoms:
Two important properties of carbon atom enable carbon to form enormously large
number of compounds.
CATENATION : property of carbon atom to form bond with other atoms of
carbon is called catenation. Like carbon, silicon forms compounds with hydrogen
upto seven or eight atoms of silicon.
32 X – Science
AK
