Intermolecular forces are the attractive or repulsive forces that act between molecules, distinguishing them from the intramolecular forces, which hold atoms together within a molecule. These forces determine the physical properties of matter, such as boiling point, solubility, and surface tension. The primary types of IMFs include the weak dipole-dipole interactions that occur between polar molecules, the stronger hydrogen bonds formed by hydrogen atoms bonded to highly electronegative atoms like nitrogen, oxygen, or fluorine, and the general London dispersion forces, which exist between all atoms and molecules due to temporary fluctuations in electron density. The magnitude of these forces dictates how easily a substance can transition between solid, liquid, and gaseous states.