Question

Except for helium, how many electrons do noble gases have in their outer energy levels?

Answer 1

We know that the noble gases are the elements present in group 18 of the periodic table. The names of the noble gases are helium (He), neon (Ne), argon (Ar), xenon (Xe), Krypton (Kr) etc. These gases are known as inert gases.

Complete step by step answer:
Noble gases have 8 electrons in their valence shell, that means, its electronic configuration is completely filled and this is why it cannot undergo reaction with other elements. So, the noble gases are known as inert gases. Let’s understand with the help of an example. The electronic configuration of neon is 2,8 or $1{s^2}2{s^2}2{p^6}$(8) electrons in valence shell. Helium is the only noble gas which has only 2 electrons in the valence shell but it is completely filled. So, it also shows the inert nature.

Additional Information:
Let’s discuss some of the chemical properties of noble gas. They have no odour, no colour and inflammable. They exist as monatomic species such as He, Ne etc. They are good conductors of electricity. They are not soluble in water. They have a complete octet which makes them highly stable. So, they do not undergo reactions with other elements.

Note: It is to be remembered that noble gases are used for various purposes. Helium is used in weather balloons because of its good flame level and it is very light. Neon is used in advertising bulbs. In the purpose of welding, argon is used to create an inert environment. Radon is radioactive in nature and it is used in treating cancer.