Question

(a) The band theory of solids can be used to qualitatively explain the difference in electrical conductivity between metals, semiconductors and insulators. Assume a pure solid with no impurities added and answer the following questions. (i) What do the energy bands represent in a solid. (2) (ii) What is the relationship between these bands in the solid and the quantum levels of electrons in an individual atom ? (2)

Answer 1

of a solid partially filled band of soliel of aloms (1020 or more ) a solid, the number of orbitals ! continuous band of energy rather than discrele energy individual atom. The interval which do not have orbilal forms the band a) Electronic Band Structure describes the range of energy levels that electrons can have with in it as well as that can not range of energy have the election with in it There are many bands as well as band gaps that a solid Con have but the most importens bands are - Conclusion Band at is the lowest band empty the solid of Valend Band it is highest fully or The most im the important gap is enegy band gal which is the the clipperence blw conduction band & valence bene b) The electrons in an individual atom ocupy alumic orbibels, which forms a discrele set of enorgy level, also known as quanlum energy level of several alom are brought together into a molecule, atomic orbitel split into molecular orbitals large gether to form exceedingly lorrge. as well as the difference blo than very of no are Bu Similarly, when a brought together becamos orbitals becomes small. Thus in solid, they form level