Noble gases have a full valence shell, which means they have the maximum number of electrons that their outermost shell can hold. The electron configurations of noble gases are as follows:

* Helium (He): 1s²

* Neon (Ne): 1s² 2s² 2p⁶

* Argon (Ar): 1s² 2s² 2p⁶ 3s² 3p⁶

* Krypton (Kr): 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶

* Xenon (Xe): 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶

* Radon (Rn): 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶

The electron configurations of noble gases are characterized by a full outermost shell, which is why they are so stable and unreactive.