Chemical bond- Attraction between atoms
A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electromagnetic force attraction between opposite charges, either between electrons and nuclei, or as the result of a dipole attraction. The strength of chemical bonds varies considerably; there are "strong bonds" such as covalent or ionic bonds and "weak bonds" such as dipole−dipole interactions, and hydrogen bonding.
What is Chemical Bonding?
A bond is formed when two atomic nuclei attract the same electrons. Energy is released
when a bond is formed, and energy must be supplied to break a bond. Atoms bond to
acquire a stable configuration, a completed outer shell. The atoms in molecules, crystals, metals, diatomic gases and most of the physical
environment around us are held together by chemical bonds.
Molecular shapes, the
three−dimensional arrangements of the atoms that constitute – a molecule are determined
by the nature of bonds between atoms in a molecule. Molecular geometry determines
several properties of a substance including its reactivity, polarity, phase of matter,
color, magnetism, and biological activity and hence there is no topic more fundamental
to Chemistry than the nature of the chemical bond.
The molecular shapes define all the life processes right from the way a biological
"cell" works, the way nerve impulses are communicated and the way immune system
works. Genes function when certain nucleic acid molecules fit into specific regions
of other nucleic acid. Hydrogen bonding, for example, plays an important role in determining
the three−dimensional structures adopted by proteins and nucleic bases.
macromolecules, bonding between parts of the same macromolecule causes it to fold
into a specific shape, which helps determine the molecule's physiological or biochemical
role. The double helical structure of DNA, for example, is due largely to hydrogen
bonding between the base pairs, which link one complementary strand to the other
and enable replication.