Ionic Bond
In
a simplified view of an Ionic bond, the bonding electron is not shared at all,
but completely transferred. In this type of bond, the outer atomic orbital of
one atom has a vacancy which allows addition of one or more electrons. These
newly added electrons potentially occupy a lower energy-state (effectively
closer to more nuclear charge) than they experience in a different atom. Thus,
one nucleus offers a more tightly bound position to an electron than does
another nucleus, with the result that one atom may transfer an electron to the
other. This transfer causes one atom to assume a net positive charge, and the
other to assume a net negative charge. The bond thus results form electrostatic
attraction between the atoms become positive or negatively charged ionic. For
example consider formation of an ionic compound like sodium chloride.
Na
" Na+ + electron
Cl
+ electron " Cl-
When
sodium and chlorine react together the outer electron of the sodium atom is
transferred to the chlorine atom to produce sodium ion (Na+) and
chlorine ion (Cl -). Electrostatic attraction between the positive
and negative ionic together in the crystal Lattice. Such bonds have no particular
orientation in space, since they result from equal electrostatic attraction of
each ion to all ions around them. So, it is crystal clear that ionic bonds are
non-directional consequently ionic compounds do not have a shape. Ionic bonds
are strong and thus ionic substances require high temperatures to melt. Ionic
compounds are brittle since the forces between ions are short-range, and do not
easily bridge cracks and fractures.
No comments:
Post a Comment