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Why can metals conduct electric current?

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Bohr model diagram of a hydrogen atom showing a green nucleus labeled H, a single electron orbit, and text with atomic mass 1.008 and electron configuration 1. — atom The Bohr model describes the structure of atoms, in this case hydrogen.

Metals are able to conduct electric current because of the unique behavior of their valence electrons. In a metallic solid, the outermost electron shells of neighboring atoms overlap, causing these electrons to become nonlocalized.21

Rather than being bound to specific atoms, these valence electrons form a "sea" of mobile, free-roaming particles that can move easily throughout the entire crystal structure. When an electrical field or voltage is applied, these electrons accelerate and migrate through the solid, creating an electric current.234

The effectiveness of this conductivity depends on two primary factors:
* Electron Mobility: The ease with which electrons can move through the lattice when influenced by an electric field.41
* Crystal Purity: Impurities or defects in the crystal structure can scatter electrons, which interferes with their movement and increases the metal's resistivity.41

While the number of free electrons contributes to conductivity, high mobility—as seen in metals like silver—can make a metal a better conductor than one with a higher density of electrons but lower mobility.41