Question

what is noble metals

Answer 1

Noble metal means which atoms have no electrons in outermost shell it's means that its outer layer have fully filled.

Answer 2

The noble metals are a group of metalsthat resist oxidation and corrosion in moist air. The noble metals are not easily attacked by acids. They are the opposite of the base metals, which more readily oxidize and corrode.
for e.g. Silver, palladium,rhodium,ruthenium etc.