Chemical Bonding: 

It is a bond which is obtained by mutual sharing or complete transfer of electrons from one atom to another.chemical bond can be ionic, covalent or electrovalent in nature. If a bond is formed by mutual exchange of ions or atoms it is called as covalent bond.If a bond is formed by complete transfer of ions or atoms it is called as electrovalent compounds.

Types

Basically there are two major types namely electrovalent and covalent.as described earlier covalent bond is mostly found in majority of compounds.The next comes electrovalent bond.Examples of covalent compounds are CCl₄ and CH₄. and that of electrovalent compounds are NaCl.Carbon tetra chloride has covalency of carbon 4 which can be explained as follows .carbons atomic no is 6.So 6 can be splitted as 2 and 4 .now chlorines atomic no is 17,this 17 can be split up as 2,8,7.chlorine is in deficit of 1 electron ,now this one electron can be supplied by carbon atom.since the carbon atom is flanked by 4 chloride atoms ,the 4 chloride atoms take the 4 electrons of carbon.in return carbon shares 4 electrons from each chloride atom.

Rules for Electron Dot structures and Bonding Structures: 

• The central atom follows the octet rule and in most cases the least electronegative atom is surrounded by the other atoms.other atoms follow the octet rule whenever electrons are available. Drawing bonding structure called lewis structure. Select a reasonable skeleton for the molecule. The least electronegative element is the central element.except that hydrogen never is example.eg S C S in CS₂ , Oxygen atom donot bond to each other except in few cases as O₂ ,O₃
• Calculate the total no of outer shell electrons available in all the atoms of the molecule or ion.
• Draw a single bond to represent each pair of shared electron in the skeleton.
• Suppose there are more than one bond represent it as double or treble bond.
• Distribute the remaining electrons in a fashion to get an octet configuration.
• for ions be sure to add(for negative ions) and to subtract(for positive ions) the no of electrons indicated by the charge on the ion.
• In case of left over electrons,place the additional lone pair of electrons into the skeleton to fill the octet of every group 1,2, 13, 14, 15, 16 ,17 element except H₂.