Question

The atomic number of an element 'y' is 20. The electronic configuration of the ion having inert gas configuration is:
(A) $2,8,10$
(B) $2,18$
(C) $2,10,8$
(D) $2,8,8$

Answer 1

Firstly we should be clear that what exactly is the inert gas and the reason for its inertness. Now after that we get that because they follow the octet rule and they also follow the Aufbau’s principle they show the inert nature.

Complete answer: Firstly we should be aware of the concept of the inert gas and the properties that makes it so inert.
Now we have to apply a specific step by step approach towards finding the electronic configuration, as it is the number of electrons present per shell or they are the numbers that signifies it.
Talking about the inert gases we know for a fact that all the inert gases have a property that they have fully filled valence shells. Apart from that they also do not react with other atoms to form molecules.
Now according to the octet law and the general filling of the electrons accordingly we can say that the electronic configuration of inert gas is the property that shows that these gases do not participate in reactions with other elements.
Now the mentioned gas is the gas named as Argon.
Electronic configuration of Argon: $Ar\left( {2,8,8} \right)$
This shows that inert gases are quite stable.

Therefore the correct option would be option(A), $2,8,8$ .

Note: The name "argon" is derived from the Greek word ἀργόν, neuter singular form of ἀργός meaning "lazy" or "inactive", as a reference to the fact that the element undergoes almost no chemical reactions. The complete octet (eight electrons) in the outer atomic shell makes argon stable and resistant to bonding with other elements.