Question

The last member of the family of the inert gases is:
A. Argon
B. Radon
C. Xenon
D. Neon

Answer 1

The noble gases also known as the inert gases; sometimes referred to as aerogenes with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low chemical reactivity.

Complete step by step answer:
The six naturally occurring noble gases are helium ($He$ ) are neon ($Ne$ ), argon ($Ar$ ), krypton ($Kr$ ), xenon ($Xe$ ), and the radioactive radon ($Rn$ ). The noble gases have weak interatomic force, and consequently have very low melting and boiling points. They are all monatomic gases under standard conditions, including the elements with larger atomic masses than many normally solid elements.
The noble gas atoms, like atoms in most groups, increase steadily in atomic radius from one period to the next period due to the increasing number of electrons. From top to bottom, the elements are lined up in the group 18 as follows: Neon, Argon, Xenon, Radon.

So, the correct answer is Option B.

Note: For the first six periods of the periodic table, the noble gases are exactly the members of group 18. Noble gases are highly unreactive except when under particular extreme conditions. The inertness property of noble gases is very suitable for the reactions. For example, argon is used in incandescent lamps for the prevention of the hot tungsten filament from oxidizing; also, helium is used in breathing gas by deep-sea divers to prevent oxygen, nitrogen and carbon dioxide (hypercapnia) toxicity.