Answer:
All noble gases.
Helium (He), neon (Ne) , argon (Ar) , krypton (Kr ), xenon (Xe), radon (Rn)
Explanation:
All noble gases have complete outer shells.These are six elements Helium (He), neon (Ne) , argon (Ar) , krypton (Kr ), xenon (Xe), radon (Rn). These all are non reactive and stable.
Electronic configuration of Helium.
He₂ = 1s²
Electronic configuration of neon.
Ne₁₀ = [He] 2s² 2p⁶
Electronic configuration of argon.
Ar₁₈ = [Ne] 3s² 3p⁶
Electronic configuration of krypton.
Kr₃₆ = [Ar] 3d¹⁰ 4s² 4p⁶
Electronic configuration of xenon.
Xe₅₄ = [Kr] 4d¹⁰ 5s² 5p⁶
Electronic configuration of radon.
Rn₈₆ = [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶
we can see in case of all element the outer shell is complete.
