Difference between revisions of "TFNR - Molecules"

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Molecules (including polyatomic ions) are '''aggregates of two or more atoms held together by chemical bonds'''.
  
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion.[4][5][6][7][8] In quantum physics, organic chemistry, and biochemistry, the distinction from ions is dropped and molecule is often used when referring to polyatomic ions.
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They may be formed by '''atoms of the same species, or by different chemical elements'''.  
  
A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (two hydrogen atoms and one oxygen atom; H2O). In the kinetic theory of gases, the term molecule is often used for any gaseous particle regardless of its composition. This relaxes the requirement that a molecule contains two or more atoms, since the noble gases are individual atoms.[9] Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are typically not considered single molecules.[10]
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Atoms can be connected by '''different types of bonds''': covalent bonds, polar covalent bonds, ionic bonds, metallic bonds, etc. In molecules some electrons can be shared by tow or more atoms, or they can be shared by several molecules and become like an electronic cloud which gives particular properties to the compound (eg in metals).
  
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Molecules are the '''constituent elements of compounds''', one of the fundamental objects of study of chemistry and molecular physics.
  
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'''The spatial extent of molecules can range from the very little size''' of the smallest, diatomic hydrogen (with a bond length of 0.74 * 10<sup>-10</sup> meters) '''to the macroscopic sizes''' of molecules of many inorganic and organic polymers ((such as  proteins and DNA), in the order of about 10<sup>-10</sup> to 10<sup>-9</sup>.
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As with atoms, the '''size and shape of molecules depend on the state and dynamics of the molecule and the state and dynamics of the molecular environment''' (on the compounds of which the molecule take part). '''Properties of molecules can be intrinsic''', mainly due to the interactions with (bonds) and the collective behavior of the atoms (and in turn of the atomic particles, nucleus and electrons) that compose them, '''and extrinsic''', due to the interactions and collective behavior or the molecules in the compound.
  
 
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Latest revision as of 19:14, 2 September 2023

Molecules (including polyatomic ions) are aggregates of two or more atoms held together by chemical bonds.

They may be formed by atoms of the same species, or by different chemical elements.

Atoms can be connected by different types of bonds: covalent bonds, polar covalent bonds, ionic bonds, metallic bonds, etc. In molecules some electrons can be shared by tow or more atoms, or they can be shared by several molecules and become like an electronic cloud which gives particular properties to the compound (eg in metals).

Molecules are the constituent elements of compounds, one of the fundamental objects of study of chemistry and molecular physics.

The spatial extent of molecules can range from the very little size of the smallest, diatomic hydrogen (with a bond length of 0.74 * 10-10 meters) to the macroscopic sizes of molecules of many inorganic and organic polymers ((such as proteins and DNA), in the order of about 10-10 to 10-9.

As with atoms, the size and shape of molecules depend on the state and dynamics of the molecule and the state and dynamics of the molecular environment (on the compounds of which the molecule take part). Properties of molecules can be intrinsic, mainly due to the interactions with (bonds) and the collective behavior of the atoms (and in turn of the atomic particles, nucleus and electrons) that compose them, and extrinsic, due to the interactions and collective behavior or the molecules in the compound.

Links to the tables of contents of TFNR Paper