OganessonElectron Configuration, Bohr Model, Valence Electrons & Orbital Diagram

The electron configuration of Oganesson is written as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 5f¹⁴ 6d¹⁰ 7s² 7p⁶. Applying the Aufbau principle — filling orbitals from lowest to highest energy — plus the Pauli Exclusion Principle and Hund's Rule, we systematically place all 118 electrons: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 5f¹⁴ 6d¹⁰ 7s² 7p⁶. The p-subshell adds three dumbbell-shaped orbitals (p_x, p_y, p_z) that collectively hold up to 6 electrons. In Oganesson, these outermost p-orbitals are the seat of its chemical personality — nearly complete and hungry for one more electron.

Oganesson follows the standard Aufbau filling order without exception. The noble gas shorthand [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶ replaces the inner-shell electrons with the symbol of the preceding noble gas, highlighting that only the outer electrons — 5f¹⁴ 6d¹⁰ 7s² 7p⁶ — are chemically active. Note: for Period 4+ elements, the 4s orbital fills before 3d per Madelung's rule, even though 3d ends at a lower energy in the final atom.

Shell-by-shell, Oganesson's 118 electrons are distributed as: K-shell (n=1): 2 electrons; L-shell (n=2): 8 electrons; M-shell (n=3): 18 electrons; N-shell (n=4): 32 electrons; O-shell (n=5): 32 electrons; P-shell (n=6): 18 electrons; Q-shell (n=7): 8 electrons. The Q-shell (n=7) is the valence shell, containing 8 electrons.

Chemically, this configuration places Oganesson in Group 18 with oxidation states of 6, 4, 2, 0. A completely filled valence shell means no empty orbital is available for bonding — chemical inertness is the thermodynamic consequence.

The SPDF orbital model describes Oganesson's electrons not as planetary orbits but as three-dimensional probability clouds — each orbital a region of space where an electron is most likely to be found. Oganesson's 118 electrons occupy 19 distinct subshells: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 5f¹⁴ 6d¹⁰ 7s² 7p⁶, governed by three quantum mechanical rules.

The Pauli Exclusion Principle ensures no two electrons in Oganesson share the same four quantum numbers (n, l, m_l, m_s). This is why the 1s orbital holds only 2 electrons, the full p-subshell holds 6, d holds 10, and f holds 14. Without this rule, all 118 electrons would collapse into the 1s orbital. Hund's Rule of Maximum Multiplicity is critical in Oganesson's p-subshell: the three p-orbitals (p_x, p_y, p_z) must each receive one electron before any pairing occurs. This minimizes electron-electron repulsion and explains Oganesson's 5 paired and -2 empty p-orbitals.

Following standard orbital filling, Oganesson fills orbitals in the sequence: 1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p → 5s → 4d → 5p → 6s → 4f → 5d → 6p → 7s → 5f → 6d → 7p. The final electron enters the 7p⁶ subshell, making Oganesson a p-block element with 8 valence electrons in Group 18.

The outermost electrons — 7p⁶ — are Oganesson's chemical agents. With a full outer shell, there are no accessible empty orbitals. No bond can form without violating the energy-stability of the closed-shell configuration.

Oganesson's chemical reactivity is shaped by three interlocking properties: electronegativity, first ionization energy, and electron affinity (0 eV). Its electronegativity is not measurable (noble gas — no electronegativity scale applies).

Oganesson's ionization energy pattern reflects its block and period positioning, consistent with the expected periodic trend for Noble Gas elements.

Oganesson is chemically inert under all ordinary conditions. Both electron donation and acceptance are energetically unfavorable given its closed-shell ground state.

Placing Oganesson between Tennessine (Z=117) and its following element reveals the incremental property changes that make the periodic table a predictive tool.

Tennessine → Oganesson: adding one proton and one electron increases nuclear charge by 1. Valence electrons shift from 7 to 8 (Group 17 → Group 18). . Atomic radius increases from 138 pm to 152 pm, consistent with descending a group with additional shells.

Oganesson (Z=118) represents the last element in this comparative sequence.