Question

Total number of inert gases among the following is:
H, He, Ne, F, Ar, Kr, K
A.1
B.2
C.3
D.4

Answer 1

Generally, the group 18 of the periodic table consists of inert gases or noble gases. These gases are monatomic and chemically inert under normal conditions. Further, these gases are present in very small quantities in the atmosphere and hence are also known as rare gases.

Complete step by step answer:
The noble gases are also known as inert gases and these are the elements that belong to group 18 of the periodic table. The elements are Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe) and Radon (Rn). Further, these gases have stable configuration and do not form molecules easily. The general configuration of these gases is $n{s^2}n{p^6}$ and hence, the outermost valence shell of these gases is considered as full and this is the reason behind the chemically inert nature of these elements.
Some of the properties of these elements are listed below:
They have very high ionization enthalpies.
The valence shell of these gases is completely filled and the next available shell is of much higher energy.
They also have large positive values of electron gain enthalpy.
According to the modern researchers, it has been seen that these gases can be compelled to take part in a chemical reaction under specific conditions. T
So, from the given gases, the noble gases are He, Ne, Kr, and Ar

Hence, option D is correct.

Note:
There are various uses of inert gases. In metallurgical processes, argon is widely used in order to provide the necessary inert atmosphere. Moreover, helium is used in nuclear reactors as a cooling gas and as a flow gas in liquid gas chromatography. Xenon and krypton find their application in photographic flash units due to the generation of very bright light.