Question

Which element is classified as a noble gas? O N Cl Xe

Answer 1

Answer: The correct answer is Xenon (Xe).

Explanation:

Noble gases are defined as the gases which have fully filled electronic configuration or stable electronic configuration.

From the given options:

Option 1: Oxygen (O)

The atomic number of this element is 8.

Electronic configuration of this element: $1s^22^22p^4$

As, this is not the stable electronic configuration. Thus, it is not considered as a noble gas.

Option 2: Nitrogen (N)

The atomic number of this element is 7.

Electronic configuration of this element: $1s^22^22p^3$

As, this is not the stable electronic configuration. Thus, it is not considered as a noble gas.

Option 3: Chlorine (Cl)

The atomic number of this element is 17.

Electronic configuration of this element: $1s^22^22p^63s^23p^5$

As, this is not the stable electronic configuration. Thus, it is not considered as a noble gas.

Option 4: Xenon (Xe)

The atomic number of this element is 54.

Electronic configuration of this element: $[Kr]5s^24d^{10}5p^6$

As, this is a stable electronic configuration. Thus, it is considered as a noble gas.

Hence, the correct answer is Xenon (Xe).

Answer 2

Answer:

Xenon (Xe) element is classified as a noble gas.

Explanation:

Noble gas are mono-atomic species with fully filled electronic configuration and are inert in nature.

Oxygen has atomic number of 8. Its electronic configuration is : $[O]=1s^22^22p^4$

Nitrogen has atomic number of 7. Its electronic configuration is : $[N]=1s^22^22p^3$

Chlorine has atomic number of 17. Its electronic configuration is : $[Cl]=1s^22^22p^63s^23p^5$

All the above electronic configuration are not fully-filled.Hence they are not noble gases.They exist in diatomic form.

Xenon has atomic number of 54. Its electronic configuration is : $[Xe]=[Kr]5s^24d^{10}5p^6$

As, this is a fully filled and  stable electronic configuration. Thus, it is considered as a noble gas.