INTRODUCTION:
The material are broadly divided into two groups, Metal and Non-Metal. The metals are usually solid at room temperature and are malleable and ductile, and have good electrical and thermal conductivity. The other properties of metals include lustre, high density, high melting point, good strength and hardness, low specific heat etc. Most of the metals are found to be elastic to a certain limit and they deform plastically at higher stresses. A metal can exist in the solid, liquid or gaseous states depending upon the temperature and pressure exerted on the metal. some of the common metals and alloys are iron, copper, aluminium, nickel, tin, brass and bronze etc.
The non-metals in the solid state are mostly brittle and are poor electrical and thermal conductivity. They do not form alloy but combine chemically to form compound. Some of the non-metals are glass, plastics, wood, concrete etc.
STRUCTURE OF SOLIDS:
All solid substances are either amorphous solids or crystalline solids. In the amorphous solids, the atoms are arranged chaotically, i.e., the atoms are not arranged in a systematic order.
The common amorphous solids are wood, plastics, glass, paper, rubber etc. In crystalline solids, the atoms making up the crystals arrange themselves in a definite and orderly manner and form. All solid metals such as iron, copper, aluminum etc. are crystalline solids.
SPACE LATTICE:
All solid metals are made up of a number of crystals arranged themselves in a definite and orderly manner and form and each crystal consists a large number of atoms. This definite and orderly manner and form of atoms producing a geometrical shape in the aggregate is called space lattice.
