Engineering materials

 Engineering materials describe the properties of matter to various areas of science and engineering. Engineerting materilas can be categorized  depending  the type of bonding between the atoms. The most major types of bonding are classified as follows: Ionic bond, Metal bond, Covalent bond. The first type, ionic bond,  formed between a cation, which is usually a metal, and an anion, which is usually a nonmetal.  In this type of bond, the outer layer of one atom has a vacancy which allows addition of one or more electrons.Ionic bonds are strongbut also brittle, so ionic substances require high temperatures to melt. The second type, metal bond, each atom in a metal donates one or more electrons to a "sea" of electrons that reside between many metal atoms.The sea of electrons in metallic bonds causes the characteristically good electrical and thermal conductivity of metals, and also their "shiny" reflection of most frequencies of white light. Also the last type, covalent bond, here one or more electrons are drawn into the space between the two atomic nuclei.The weak bonds give organic molecular substances, such as waxes and oils, their soft bulk character, and their low melting points.The engineering materials based on the bondings.These three types of bodying are the most important and from them we can explain the behaviours of the atoms and also we can explain the properties of a material.