Intermolecular forces

Intermolecular bonds,

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In a liquid or gases there must be forces
Between the molecules causing molecules to be attracted one to another; otherwise
they would move apart from each other and become a gas. These forces are called
They are much weaker than covalent, ionic or metallic bonds. When a solid
melts and boils; it is the intermolecular forces that are broken.
When noble gases change from liquid to gas, energy is only required to separate
the atoms. There are no covalent bonds between atoms, but there are forces
holding atoms together. They have low boiling points because attractive forces
are very weak, however, the boiling point increases as the atom gets bigger
because the stronger attractive forces between them
The longer the alkanes chain higher the boiling point. There must
be strong attractive forces between the long molecules than between the short
molecules. Therefore more energy is needed to overcome attractive forces.
This occurs when a molecule has two atoms bonded together
which have different electro negativity, so that one atom
attracts the shared electrons much more than the other.
The charges on polar molecules cause weak electrostatic forces of
attraction between molecules. This forms stronger bond than instantaneous
induced dipole so more energy needed to break the bonds
When atoms bonded together have the same or very similar
electro negativity the electrons are evenly share, so permanent or
instantaneous dipole arise. For e.g. C l2

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Electrons are always moving really quickly, this leads to an uneven distribution if
charge. Therefore one atom becomes more negative than other and attracts more
electrons. This dipole can cause another dipole in the opposite direction on a
neighbouring atom and then two dipoles are attracted together.…read more

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