LONDON FORCES Meaning and
Definition
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London forces, also known as dispersion forces or van der Waals forces, are a type of intermolecular force that exists between all atoms and molecules. These forces arise due to temporary fluctuations in electron distribution, resulting in the creation of instantaneous dipoles within the molecules. As a consequence, London forces are considered the weakest among the intermolecular forces.
These forces occur because the electrons in an atom or molecule are constantly in motion. Occasionally, a slight imbalance in electron distribution can lead to the formation of a temporary dipole moment. This transient dipole can induce dipoles in nearby molecules, causing an attractive force between them. Even though the effect of London forces is short-lived and weak, they play a significant role in intermolecular attractions, particularly for nonpolar molecules.
The strength of London forces depends on the size of the electron cloud, which is influenced by the number of electrons and the shape of the molecule. The larger the atom or molecule, the greater the number of electrons, resulting in more extensive fluctuations in electron distribution and stronger London forces.
London forces are essential in determining the physical properties of substances such as boiling points, melting points, and the ability to dissolve in various solvents. Additionally, they are also responsible for the adherence of nonpolar molecules to surfaces and the cohesion between molecules in liquids.
Etymology of LONDON FORCES
The term "London forces" refers to a specific type of intermolecular force, also known as dispersion forces, which exist between atoms or molecules. These forces were first described by the German physicist Fritz London in 1930, and thus, they were named after him.
Fritz London's research focused on understanding the nature of intermolecular forces, particularly the attractive forces that arise between nonpolar molecules. He explained that these forces are the result of temporary fluctuations in electron distribution around an atom or molecule, creating temporary dipoles. These temporary dipoles induce similar fluctuations in neighboring atoms or molecules, resulting in attractive forces between them.
The term "London forces" was coined to honor Fritz London's landmark contributions to the understanding of these intermolecular forces. The name has since been widely used in scientific literature and is now recognized as a fundamental concept in the field of chemistry.
