Atoms of different elements excepting noble gases do not have complete octet so they combine with other atoms to form chemical bond. The force which holds the atoms or ions together within the molecule is called a chemical bond and the process of their combination is called Chemical Bonding. It depends on the valency of atoms.
Ause and Modes of chemical combination
Chemical bonding takes place due to acquire a state of minimum energy and maximum stability and to convert atoms into molecule to acquire stable configuration of the nearest noble gas. We divide atoms into three classes,
(1) Electropositive elements which give up one or more electrons easily. They have low ionisation potentials.
(2) Electronegative elements, which can gain electrons. They have higher value of electronegativity.
(3) Elements which have little tendency to lose or gain electrons.
Different types of bonds are formed from these types of atoms.
A + B
B + B
A + A
Electrons deficient molecule or ion (Lewis acid) and electrons rich molecule or ion (Lewis base)
H and electronegative element (F, N,O)