Question

Metals like silver, gold and platinum which do not corrode and do not react with oxygen even on strong heating are called _______ metals.
a.) Noble
b.) Alkali
c.) Alkaline earth metals
d.) None of these

Answer 1

Hint: Noble gases are group 18 elements of the modern periodic table. Noble metals are those which resist oxidation even at high temperature and also resist corrosion.

Complete step-by-step answer:

The noble metals are a group of metals that do not get oxidized and corrode in moist air. The noble metals are not easily attacked by oxygen and acids and are more stable than many other compounds. This lack of chemical reactivity makes them noble metals. The noble metals are inert as they have closed shells, it means they have complete octet configuration. They are just the reverse of base metals, which easily gets oxidized and corrode in moist air.
For example:- Gold, Silver, Osmium, Palladium, Rhodium and Iridium as well.

The group 1 elements are called Alkali metals. They react with water to form an alkaline or basic solution. Initially, alkali metals are shiny grey but when they react with oxygen they quickly become dull and white. This process is known as Tarnishing.
For example:- ${ 4Li+ }{ O }_{ 2 }\rightarrow { 2Li }_{ 2 }{ O }$

The group 2 elements are called Alkaline earth metals. These also react with oxygen just like group 1 elements. These reactions also require heating. When these metals react with oxygen they simply form metal oxides.

Hence, we can say that metals like silver, gold and platinum which do not corrode and do not react with oxygen even on strong heating are called noble metals.

Note: The possibility to make a mistake is that noble metals are less reactive as they have fully filled electronic configuration while alkaline earth metals are also less reactive due to the presence of 2 electrons in its outermost shell but they are more reactive than noble metals.