noble metals are metals that are resistant to corrosion and oxidation in humid air (unlike most non-ferrous metals). A short list of chemically noble metals (those elements on which almost all chemists agree) contains ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), osmium (Os), iridium (Ir), platinum (Pt ) and gold (Au).
More included listings include one or more of mercury (Hg), rhenium (Re) and copper (Cu) as noble metals. On the other hand, titanium (Ti), niobium (Nb) and tantalum (Ta) are not included as noble metals, although they are very resistant to corrosion.
A collection of noble metals, including copper, rhenium and mercury, which are included in some definitions. They are arranged according to their position on the periodic table.
While precious metals are generally valuable - both due to their rarity in the earth's crust and their use in fields such as metallurgy, high technology, and jewelry (jewelry, arts, sacred objects, etc.) - in terms of precious metals and precious metals are not synonymous.
The term noble metal can be traced back to at least the late 14th century and has several different meanings in various fields of research and application. Only in atomic physics is there a rigorous definition that includes only copper, silver and gold, because they are completely filled with d-subshells. For this reason, there are many completely different lists of "noble metals".
In addition to the function of this term as a compound noun, there is a circumstance where noble is used as an adjective for a metal noun. An electroplating series is a hierarchy of metals (or other electrically conductive materials, including composite materials and semimetals) that goes from noble to active, and allows you to predict how materials will interact in the environment used to create the series. In this sense, graphite is nobler than silver, and the relative nobility of many materials is highly context dependent, as is the case for aluminum and stainless steel at different pH conditions.