How many and which are the types of molecular forces?

Molecular forces are forces of attraction between
different molecules.

There are four general types of
molecular forces:

Type 1  - Ionic forces. These are the
strongest types of forces because of the strong attraction between positively charged
and negatively charged ions. Crystals of salt are an example of this type of molecular
force. These materials have very high melting points.

type
2 - dipole to dipole forces.  A dipole exists in a molecule when one part of the
molecule has a relative positive charge while another part of the same molecule has a
relative negative charge.  Hydrogen chloride gas is an example of a dipole molecule. The
hydrogen has a relatively positive charge while the chlorine has a relatively negative
charge. The molecules in the gas will orient themselves so oppositely charged parts of
the molecules are aligned.

type 3 - hydrogen bonding. This
is really a type of dipole to dipole attraction because of how common and important it
is to life on earth.

type 4 - induced dipoles which are the
weakest type of attraction. Because electrons are relatively free to move around within
many substances, the electron clouds around the nucleus can temporarily shift. This
shift causes a corresponding shift in another adjacent molecule and a small, momentary
attraction between the two molecules.