Intermolecular forces are responsible for the physical properties of a substance, such as its melting or boiling point, viscosity, solubility, surface tension and evaporation. The types of intermolecular forces are ionic, hydrogen bonding, dipole and induced dipole forces. Except ionic force, all other intermolecular forces occur between neutral molecules, which have a slight polarity.Know More
Ionic forces occur between two ions. The ions may have been formed from neutral atoms or molecules. For example, a neutral sodium atom can lose an electron to a neutral chlorine atom to form sodium chloride, which has a sodium and chlorine ion.
Some covalent bonds are formed by unequal sharing of electrons. One molecule ends up with a partial negative charge and the other with a partial positive charge, thereby making the molecule polar. The molecules are still considered to be neutral since no electrons were exchanged in the process of forming the bond. These molecules are said to be polar molecules or dipoles, and the force between them is called a dipole force.
Nonpolar molecules can distort the electron cloud slightly to become temporary dipoles. They are held together by a weak force called the induced dipole force. The strength of the force depends on the size of the molecule and the ease with which the electron cloud can be moved or distorted.
Hydrogen bonds are a special kind of dipole force involving hydrogen bonding to an electronegative element such as oxygen or nitrogen.Learn more about Atoms & Molecules
The stronger the intermolecular forces, the more energy it takes to overcome these interactions and to cause the substance to boil. Therefore, molecules with strong bonds have high boiling points, and molecules with weak bonds have lower boiling points.Full Answer >
There are three intermolecular forces of ethanol. They are London dispersion, dipole-dipole and the hydrogen bond. All three of these forces are different due to of the types of bonds they form and their various bond strengths.Full Answer >
The attractive forces that hold the molecules of a liquid together are always the result of opposite charges from the opposite ends of polar molecules, although that polarity is not always inherent to the molecules involved. Even the electrons of molecules, which are not polar, are in constant motion, and in the presence of another molecule, momentary induced dipoles can be created. These are much weaker than inherent dipoles, however.Full Answer >
In order for a substance to melt, it must absorb enough energy to overcome the intermolecular bonds holding its molecules together. These bonds may be ionic, molecular, covalent or metallic, depending on the material involved. Ionic bonds require the most energy to overcome, while molecular bonds are easier to break.Full Answer >