NihoniumElectron Configuration, Bohr Model, Valence Electrons & Orbital Diagram

The electron configuration of Nihonium is written as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 5f¹⁴ 6d¹⁰ 7s² 7p¹. Applying the Aufbau principle — filling orbitals from lowest to highest energy — plus the Pauli Exclusion Principle and Hund's Rule, we systematically place all 113 electrons: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 5f¹⁴ 6d¹⁰ 7s² 7p¹. The p-subshell adds three dumbbell-shaped orbitals (p_x, p_y, p_z) that collectively hold up to 6 electrons. In Nihonium, these outermost p-orbitals are the seat of its chemical personality — partially filled, enabling versatile bond formation.

Nihonium follows the standard Aufbau filling order without exception. The noble gas shorthand [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p¹ replaces the inner-shell electrons with the symbol of the preceding noble gas, highlighting that only the outer electrons — 5f¹⁴ 6d¹⁰ 7s² 7p¹ — 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, Nihonium's 113 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): 3 electrons. The Q-shell (n=7) is the valence shell, containing 3 electrons.

Chemically, this configuration places Nihonium in Group 13 with oxidation states of 3, 1. This configuration directly predicts Nihonium's bonding mode, reactivity toward oxidizing and reducing agents, and the stoichiometry of its most common compounds.

The SPDF orbital model describes Nihonium'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. Nihonium's 113 electrons occupy 19 distinct subshells: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 5f¹⁴ 6d¹⁰ 7s² 7p¹, governed by three quantum mechanical rules.

The Pauli Exclusion Principle ensures no two electrons in Nihonium 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 113 electrons would collapse into the 1s orbital. Hund's Rule of Maximum Multiplicity is critical in Nihonium'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 Nihonium's distribution of electrons across separate p-orbitals.

Following standard orbital filling, Nihonium 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 7p¹ subshell, making Nihonium a p-block element with 3 valence electrons in Group 13.

The outermost electrons — 7p¹ — are Nihonium's chemical agents. Understanding the 7p¹ occupancy — how many electrons, whether paired or unpaired, the orbital shape involved — is the foundation for predicting Nihonium's bonding geometry, oxidation behavior, and compound formation.

Nihonium'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).

Nihonium's ionization energy pattern reflects its block and period positioning, consistent with the expected periodic trend for Post-Transition Metal elements.

In standard chemical conditions, Nihonium forms predominantly +3 oxidation state compounds, consistent with its 3 valence electrons and p-block character.

Placing Nihonium between Copernicium (Z=112) and Flerovium (Z=114) reveals the incremental property changes that make the periodic table a predictive tool.

Copernicium → Nihonium: adding one proton and one electron increases nuclear charge by 1. Valence electrons shift from 12 to 3 (Group 12 → Group 13). . Atomic radius increases from 122 pm to 170 pm, consistent with descending a group with additional shells.

Nihonium → Flerovium: the additional proton and electron in Flerovium changes the valence electron count from 3 to 4, crossing from Group 13 to Group 14. Both elements share Post-Transition Metal character, with Flerovium exhibiting slightly different electronegativity. These comparisons confirm that Nihonium sits at a well-defined chemical inflection point in the periodic table.