State whether each sentence is true or false: (a) Metals have high electrical conductivities because the electrons in the metal are delocalized. (c) Metals have large thermal conductivities because they expand when heated. (d) Metals have small thermal conductivities because the delocalized electrons cannot easily transfer the kinetic energy imparted to the metal from heat.

Key Concepts

Delocalized Electrons

Delocalized electrons are electrons in a metal that are not bound to a specific atom and can move freely throughout the metal lattice. This mobility allows metals to conduct electricity efficiently, as these electrons can carry charge across the material. The presence of delocalized electrons is a key characteristic of metallic bonding, contributing to the unique properties of metals.

Thermal Conductivity

Thermal conductivity is a measure of a material's ability to conduct heat. In metals, high thermal conductivity is primarily due to the presence of free-moving electrons, which can transfer kinetic energy rapidly throughout the material. This property allows metals to efficiently transfer heat, making them suitable for applications requiring good thermal management.

Effect of Heating on Metals

When metals are heated, they typically expand due to increased atomic vibrations. This expansion can affect thermal conductivity, but it does not inherently reduce it. The ability of delocalized electrons to transfer energy remains effective even as the metal expands, allowing for continued efficient heat transfer. Therefore, the statement that metals have small thermal conductivities due to expansion is false.