Solids
are characterized by incompressibility, rigidity and mechanical
strength. This represent the molecules, atoms or ions that make up a
solids which are closely packed. They are join together by strong
cohesive forces and cannot move at random. Thus, in solids we have well
ordered molecular atomic or ionic arrangements. Thus, it is extremely
hard to break atomic bonds between these molecules.
Some solids like sodium chloride NaCl2,
sulphur S, and sugar (carbohydrates), besides being incompressible and
rigid, have also characteristic geometrical forms. Such substances are
known be a crystalline solids. The X-ray crystallography studies reveal
that their ultimate particles such as molecules, atoms or ions are
arranged in unusual pattern throughout the entire three-dimensional (3D)
network of crystal. This definite and ordered arrangement of molecules,
atoms or ions lengthens over a large distance making it extra difficult
in breaking atomic bonds.
The natural history of the Inter-atomic Force resulting in the breaking atomic bonds
Basically,
an atom consists of a tiny positively charged body, located at its
center called as nucleus. The nucleus, though small have all the protons
and neutrons. Since the mass of an atom entirely owing to the presence
of protons and neutrons, it is evident that almost the entire mass of an
atom resides in the nucleus.
Between
the atoms or ions or molecules the inter-atomic bonds is present. This
type of breaking atomic bonds is set up by equilibrium between
attractive and repulsive forces with the remaining force being zero (0).
When the breaking atomic bonds is at stabile. It is evident that the
atoms are far apart from the attractive forces between these molecules
so it will govern and when they are very close packed together the
repulsive force will becomes higher; both these help in ruining away as
the separation increases. This report proves that the breaking atomic
bonds result from inter-atomic force, as a function of atom separation.
Fig 1: Representation of bonds between two molecules
Breaking atomic bonds is also characterized by bond energies
Enthalpy formation of the bond.
Bond
energy for any particular type of bond in a compound may be defined as
the average amount of energy required to dissociate (to break) one mole, viz., Avogadro’s number of bonds of that type present in the compound. Bond energy is also called the enthalpy of formation of the bond.