Based on the energy band theory, answer the following questions: (a) what is energy bands? what is the fermi energy and the work function of a metal? (b) hybridization is a phenomenon that happens when some particular atoms are bonded together. a sp^3 hybridization usually happens in the case of silicon atoms, and this hybridization eventually results in the formation of two special energy bands. explain how this phenomenon happens, how it results in that two energy bands, and what are that two special energy bands?