Page 54 - Chemistry ICSE Class X

42 ICSE Chemistry – 10

Carbon dioxide molecule (CO )
2
Carbon dioxide is a compound containing carbon and oxygen. The
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% K L 1 K L
,
,
2 4 2 6
Thus, each carbon atom requires four electrons and each oxygen
atom requires two electrons to complete their octets. This is done by sharing
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In carbon dioxide (CO ) molecule, carbon is linked to two oxygen
2
atoms by carbon-oxygen double bonds as shown above.

Hydrogen cyanide molecule (HCN)
Hydrogen cyanide is a compound containing one atom each of
hydrogen, carbon and nitrogen. Atoms of hydrogen and nitrogen share
their electrons with carbon atom in such a way that the carbon atom
has hydrogen and nitrogen atom on either side. Carbon atom shares
one electron pair with hydrogen atom and three electron pairs with
nitrogen atom. Thus, in hydrogen cyanide molecule there is one C – H
single bond, and one C { 0 VTKRNG DQPF CU

Covalent Compounds

What are covalent compounds
The compound formed due to mutual sharing of electrons between the
constituent atoms is called covalent compound. Covalent compounds
OC[ CNUQ DG FGſPGF CU the compounds in which the constituent atoms
are bonded to each other by covalent bonds.
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Water (H O), Ammonia (NH ), Methane (CH ), Hydrogen chloride
4
3
2
(HCl).
What are the characteristics of covalent compounds
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ƒ .QY OGNVKPI CPF DQKNKPI RQKPVU Covalent compounds consist of
molecules held by weak forces. These can be easily overcome by
heat. Thus, EQXCNGPV EQORQWPFU JCXG NQY OGNVKPI CPF NQY DQKNKPI
points.
ƒ 0QPEQPFWEVKPI PCVWTG Covalent compounds do not conduct
electricity, i.e., electricity does not pass through the covalent
compounds. This is because the covalent compounds do not contain
ions, or free electrons. Sugar is a covalent compound, and its solution
does not conduct electricity. Solutions of polar covalent compounds