Why are metals good conductors of electricity whereas glass is a bad conductor of electricity ? Give reason.

Solution:
Metals are good conductors of electricity because they contain a very large number of free valance electrons. These free electrons are carriers of charge. At the same time, glass is super-cooled molten sodium silicate and calcium silicate. And does not contain any free electrons to conduct electricity. So metals are good conductors whereas glass is a bad conductor of electricity.