Explain the inertness of noble gases

The noble gases (group 0) are incredibly inert. Indeed if we are performing reactions that are sensitive to air we will often perform them under an atmosphere of Argon, the third noble gas. But why?We must look to the electronic structure of these elements. We know that each electron shell can hold a maximum number of electrons. The first shell can hold a maximum of 2 electrons, the second 8 and the third 8 also. When elements react their electrons in the outermost electron shells (the valence electrons) are lost, gained or shared in order to fill them. For example sodium has an electron configuration of 2,8,1 that final electron can easily be given away in a chemical reaction to achieve an electron configuration of 2,8 and this is true, sodium is highly reactive it will react violently with water.So back to the noble gases, what is their electronic structure? Helium has an electronic configuration of 2, neon has 2,8 and argon has 2,8,8. All of the electron shells are completely filled, they are already very stable. They have no tendency to lose, gain or share electrons, this also explains why these elements do not form elemental molecules.