The dots around fluorine atom shows the valence electrons of
respective atoms.
The chemical bond formed between two atoms by mutual sharing of a
pair of valence shell electrons so that both of them can attain octet or
duplet in their valence shell is called the covalent bond.
The prefix co – is used to indicate when things are equal or joined.
(for example, co exist, cooperate etc). Here each atom contributes one
electron from the valence shell for the bonding. Therefore, the name
covalent is given (equal valence electrons contribution) for this bond.
The electronic configuration of 8
O is 2, 6. Oxygen atom has six
electrons in its valence shell. It requires two more electrons to get octet
in its valence shell. Therefore oxygen atoms come close and each oxygen
atom contributes two electrons for bonding. Thus, there exist two covalent
bonds between two oxygen atoms in O2
molecule as there are two pairs of
electrons shared between them.
We can say that a double bond is formed between two oxygen atoms in
O2
molecule. Observe the following figures. Both the oxygen atoms have octet in the valence shell
The electronic configuration of ‘N’ atom is 2,5 and to have octet in the valence shell it requires three more electrons. When two nitrogen atoms approach each other, each atom contributes 3 electrons for bonding. There are six electrons shared between two nitrogen atoms in the form of three pairs. Therefore, there is a triple bond between two nitrogen atoms in N2 molecule.