All solids expand on heating, especially metals. Railway lines can buckle on hot days because of this expansion. If the atoms are arranged in a regular sequence, a crystal results. Metals and salts are crystaline. Glass is a good example of an amorphous solid.
Metals are crystaline because their atoms are arranged in a regular sequence.
However, atoms of metals tend to have loose outer electrons. These electrons can move between atoms. This causes the metal to conduct electricity. The Liquid State Liquids have a fixed volume but take the shape of the container. In a liquid, the atoms move relative to one another but still stay close together.