Band gaps arise in periodic lattices due to the arrangement of atoms, which creates a band structure that includes gaps for semiconductors and insulators. According to Bloch theory, for a specific wave vector (K value), an electron within a band possesses a precise energy determined by the band’s shape. This phenomenon is akin to electrons confined in a potential well, but in a lattice, there are infinitely many potential wells. The presence of band gaps is not a direct result of Bloch theory itself, but rather a consequence of the periodic nature of the lattice. Understanding these concepts is crucial for exploring electronic properties in materials.