The 18 elements commonly referred to are the noble gases in the periodic table. Here are their names, valence electrons, valency, and electronic configurations:
Helium (He)
- Valence Electrons: 2
- Valency: 0
- Electronic Configuration: 1s²
Neon (Ne)
- Valence Electrons: 8
- Valency: 0
- Electronic Configuration: [He] 2s² 2p⁶
Argon (Ar)
- Valence Electrons: 8
- Valency: 0
- Electronic Configuration: [Ne] 3s² 3p⁶
Krypton (Kr)
- Valence Electrons: 8
- Valency: 0
- Electronic Configuration: [Ar] 3d¹⁰ 4s² 4p⁶
Xenon (Xe)
- Valence Electrons: 8
- Valency: 0
- Electronic Configuration: [Kr] 4d¹⁰ 5s² 5p⁶
Radon (Rn)
- Valence Electrons: 8
- Valency: 0
- Electronic Configuration: [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶
Oganesson (Og)
- Valence Electrons: 8
- Valency: 0
- Electronic Configuration: [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶
Note that the noble gases are chemically inert, meaning they have a valency of 0 because their outermost energy levels are fully occupied with electrons. Their electronic configurations reflect the filling of energy levels and subshells in accordance with the periodic table.