Question

Why is helium considered to be a noble gas though it has only two valence electrons, unlike the other noble gases?

Answer 1

Noble gas

• Some elements don't combine with other elements. These elements are Helium, Neon, Argon, Krypton, Xenon and Radon. They are referred to as noble gases or inert gases because they are doing not react with other elements to make compounds.
• We see that the atomic number of helium is 2 and it has a full shell of two electrons. Since there are not any electrons shielding this shell from the nucleus, these two electrons are going to be very difficult to get rid of, making helium nonreactive.
• The general electronic configuration of noble gas is ${\mathrm{ns}}^2{\mathrm{np}}^6$except helium.

Therefore, helium is considered to be a noble gas.