Question

The inert gas abundantly found in atmosphere is:
A: Argon
B: Helium
C: Xenon
D: Neon

Answer 1

Hint: Inert gases are those gases which do not undergo chemical reactions under given conditions whereas noble gases are those which do not react with many substances. Noble gases have eight electrons in their valence shell and hence these gases are highly stable. Due to this stability these gases don't react and hence are called inert gases.

Complete step by step answer:
Inert gases are those gases which do not react with any chemical compound under given conditions and noble gases are those which do not react with most of the chemical compounds. Noble gases are inert but inert gases need not be noble. Noble gases are highly stable because these gases have completely filled the outermost shell. Outermost shell of an atom is said to be filled completely when it has eight electrons. Noble gases have eight electrons in their outermost shell. Due to the high stability of these gases, these gases don’t react with other compounds.
Purified nitrogen and argon are inert gases. These gases are the major constituent of air so; these are easily available at low cost. Composition of nitrogen in air is about $78.3\% $ and composition of argon is about $1\% $. Nitrogen is not a noble gas but still can be used as an inert gas (this example proves the statement written above which says that noble gases are inert but inert gases need not be noble). Among all the gases given in options, argon is the most abundant inert gas. Symbol of argon is $Ar$.The composition of argon in air is about $1\% $.
So, the correct answer is option A.

Note:Noble gases usually do not make compounds with other elements but xenon reacts with fluorine and oxygen. Xenon has a large size, due to which the nucleus of xenon doesn’t have good hold on electrons of the outermost shell. Due to which xenon can make compounds with highly electronegative and small sized elements. Xenon makes compounds with fluorine and oxygen.