Question

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

Answer 1

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

Step-by-step 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.

Answer 2

Answer: The correct answer is Xenon (Xe).

Step-by-step 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).