Question

Noble gases are stable because their valence shell contains:

• A. 2 electrons
• B. 8 electrons
• C. both $A$ and $B$
• D. none of the above

Answer 1

The correct option is C both $A$ and $B$

Noble gases are gases which are completely filled valence shell.

Since He has only s-orbital, its outermost shell is completely filled and hence it is stable.

Other noble gases have an outer shell as p-orbital electrons along with s-orbital. So there are 8 electrons in the outermost orbital and hence it is completely filled and is stable.

Hence valence shell of noble gases contains 2 electrons in case of He and 8 electrons in case of other noble gas.