Question

Group 18 rarely combines with other elements. They are the "loners" or noble gases. Why do these elements not need to bond with other elements?

Answer 1

outermost subshells filled
valence electrons

Explanation:

The main reason the noble gases do not need to bond with other elements is that their outermost subshells are filled. These are known as valence electrons. Take helium for example. It only needs 2 valence electrons to fill its outermost subshell. The others need 8 valence electrons to be completely filled, which is the case for the rest of the noble gases.

Answer 2

The noble gases group VIII A or 18 are stable with their electron structure

Explanation:

Helium 2 has the electron configuration of `1s^2`
This has a completely filled valence shell so it is stable.

Neon 10 has the electron configuration of `1s^2 2s^2 2p^6`
This has a completely filled valence shell so it is stable.

Argon 18 has the electron configuration of `1s^2 2s^2 2p^6 3s^2 3p^6`

This has all but the 3d orbitals filled. The 3ds are a higher energy level so Argon is stable with the electron configuration of the first second and most of the third energy level filled.

This pattern continues with every element in group 18 (VIIIA) or the noble gases having a stable electron configuration.