Here's why:

* Free electrons: Silver has a unique atomic structure with a single electron loosely bound to its outermost shell. This electron can easily detach and become a "free" electron, able to move throughout the material.

* High conductivity: These free electrons allow silver to conduct electricity and heat very efficiently. In fact, silver is the best conductor of electricity among all metals.

While gold is also a good conductor, silver is actually slightly better. However, silver is more expensive and prone to tarnishing, so it's not always the practical choice for electrical applications.