ICSE CHEMISTRY - Covalent bond

ICSE CHEMISTRY - COVALENT BOND

Covalent bond:

The bond formed by the mutual sharing of electron pairs between the given pairs of atoms (of same or different kind) of non metals.

Covalent compound (molecule) : The compounds (molecules) formed as a result of mutual sharing of electrons between the atoms are called covalent compounds.

Covalency: The number of electron pairs that an atom shares with other atom/s to get stable electronic configuration.

·         The element which has 7 valence electrons (i.e. short of one electron for octet configuration) contributes one electron and shares one pair of electron with other atom.

         Cl - 2,8,7         Cl - 2,8,7                     Chlorine molecule     single covalent bond

·         The element having 6 valence electrons (short of 2 electrons) contributes 2 electrons hence shares two pairs of electrons.

Oxygen       Oxygen                 Oxygen molecule       Double bond

                 2,6               2,6

·         Similarly the element with 5 valence electrons contributes 3 electrons and shares three pairs of electrons.

           Nitrogen        Nitrogen        Nitrogen molecule

             2,5                  2,5                                                            Triple bond

·            Formation of Hydrogen molecule

·            Formation of Methane molecule (CH₄)

·         Formation of Carbon tetra chloride molecule (CCl₄)

·         Formation of Water molecule:

- Two single bonds - Two lone pairs

·         Formation of Ammonia molecule

- Three single bonds - One lone pair