Solids consist of closely packed molecules which form a rigid structure. Solids are held together by a residual electrostatic attraction which is generally weaker than a molecular bond. Solids usually consist of a simple geometric pattern of atoms or molecules which is repeated over and over again in all directions, which is known as a crystal .
Metals therefore conduct electricity very easily.
Liquids also contain closely packed molecules, but they do not have a rigid orientation. They still feel an electrostatic attraction, and they regularly bump into each other, but they can move around with relative ease. A gas whose atoms have been ionized into a mixture of positive ions and electrons is called a plasma . Stars consist of plasmas. Liquids, gases, and plasmas are all referred to as fluids , because they can flow and take the shape of whatever container they are placed in.