Introduction To Solid State Physics For Materials Engineers Pdf Verified |link| -

: This explains why materials act as metals (conductors), semiconductors, or insulators. The energy gap (band gap) between the valence and conduction bands is the most critical factor for electronic material design. Semiconductors & Devices

The smallest repeating unit that displays the full symmetry of the crystal. : This explains why materials act as metals

Understanding how atoms arrange themselves in periodic arrays. : This explains why materials act as metals