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|Subject: Moleculest Wed Dec 15, 2010 3:00 pm|| |
A molecule is defined as a group of at least two atoms in a definite arrangement held together by covalent chemical bonds. In the narrow use of the word, molecules are electrically neutral. Molecules are distinguished from polyatomic ions in this strict sense. However, in quantum physics, organic chemistry, and biochemistry, the term molecule is used less strictly and also is applied to molecular ions, charged organic molecules, and biomolecules.
In the kinetic theory of gases, the term molecule is often used for any gaseous particle regardless of its composition. According to this definition noble gas atoms are considered molecules despite the fact that they are composed of a single non-bonded atom.
A molecule may consist of atoms of a single chemical element, as with oxygen (O2), or of different elements, as with water (H2O). Atoms and complexes connected by non-covalent bonds such as hydrogen bonds or ionic bonds are generally not considered single molecules.Tattoo Removalforex training