Final answer:
Silicon's maximum resistivity occurs when it is intrinsic or pure. Introducing impurities creates extrinsic semiconductors, which have more free electrons and lower resistivity. For other materials like copper, resistance is influenced by the material's intrinsic properties and shape.
Step-by-step explanation:
Yes, silicon's maximum resistivity does occur when it is in its intrinsic (pure) state. Intrinsic silicon means that there are no impurities added to alter its electrical properties. As you introduce impurities into the silicon, creating what is known as an extrinsic semiconductor, you add free charges to the material which increases its conductivity and decreases its resistivity. For instance, adding arsenic, which has one more valence electron than silicon, creates an n-type semiconductor. These extra electrons contribute to the conductivity as they easily excite into the conduction band at room temperature. This is much the same for germanium and other semiconductors, where impurities supply free charges, thereby reducing resistivity compared to their pure state. In contrast, for non-semiconductor materials like copper, resistivity factors include shape and the intrinsic properties of the material. For example, a meter-long piece of large-diameter copper wire has a low resistance of about 10-5 ohms, indicating low resistivity due to copper's excellent conductive properties.