Question

Alkali metals are good conductors of electricity.

Answer 1

First of all, metals don't have totally "free" electrons, but metals do have electrons which are very loosely bound to atoms and that can be easily moved from one atom to the next by the application of a potential difference (an electrical voltage). 

Some models of metals treat the valance electrons as if they were a "cloud" of gaseous electrons. This model works well for making some predictions about metallic properties.