Atomic Structure

This chapter includes bonding force and binding energy, electron configuration, and crystallography as fundamental concepts used in materials science and engineering. These concepts are used to determine the crystal structures of metals, semiconductors, ceramics, and polymers. The arrangement of atoms in a crystal structure can be characterized in terms of the unit cell, which is the smallest repeating unit of the structure. The properties of a crystal, such as its critical resolved shear stress and electrical conductivity, depend on the orientation of the unit cells in the structure. In addition, quantum mechanics describes the atom as a collection of smaller particles. For instance, electrons are described as wavelike particles, and protons and neutrons are divided into quarks. Materials science treats the atoms as hard-spheres, classifies solids as crystalline structures, and divides crystalline structures into unit cells. The arrangement of atomic particles (atoms, ions, or molecules) can be characterized in terms of the smallest repeating unit cells responsible for the symmetry of a crystal structure and related properties.