Madelung’s Rule: An Ontological Derivation

Integrated from ArXe Theory and ALO

Author: Diego Luis Tentor
Status: Structural derivation — some sections confirmed, some exploratory
Date: March 2026
Mode: B (quantitative) for primary structure; A→B (exploratory) for exceptions


Abstract

We present a structural derivation of Madelung’s rule for atomic orbital filling from ArXe theory and ALO (Arity Logical Ontology). The derivation has three layers of increasing solidity:

Layer 1 — Partially superseded (updated 2026-07-30): The magnetic quantum number count (2l+1) of each orbital type corresponds exactly to the aridity of the ArXe negative levels — this part remains confirmed. The claim that the Madelung filling order is the order of decreasing coupling probability has been retracted: a later derivation (arxe_periodic_table_paper_v2_en.md §4.4) shows the filling order is an energy effect (differential nuclear phase access), not a probability effect. See the note in §3.3 below.

Layer 2 — Coherent: The (n+l) sum encodes ontological depth, and orbital energies in Planck units have ArXe-pure arity factorizations for the principal orbitals. The atom as a whole maps coherently onto the ArXe level structure.

Layer 3 — Exploratory: Madelung exceptions occur preferentially at element numbers Z that are ArXe arities. This is sugestive and structurally motivated but requires more formal derivation before being stated as a result.


1. The Phenomenon and Classical Gap

The Aufbau principle states that atomic orbitals fill in order:

1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p → 5s → 4d → 5p → 6s → 4f...

Madelung’s rule: Fill in order of increasing (n+l). For equal (n+l), fill lower n first.

This produces period lengths 2, 8, 8, 18, 18, 32, 32…

Physics derives this from the Schrödinger equation and Pauli exclusion. It does not explain why the quantum numbers take these specific values, why (n+l) is the relevant ordering quantity, or why orbital capacities are 2, 6, 10, 14…


2. The Atom as ArXe Structure

2.1 Nuclear structure

The nucleus exhibits composite structure at three ArXe levels:

T⁻³ (n=7, CPX): nuclear mass, color confinement
T⁻² (n=5, MEM): QCD confinement space
T⁻¹ (n=3, CYC): 3 quarks, ternary circular causation

In ALO terms, the nucleon (proton/neutron) in Planck units has physical integer P = 77 = 7×11 = CPX×REG — confirming T⁻³ (arity 7) × T⁻⁵ (arity 11) nuclear-EM structure.

2.2 Orbital space

The nucleus at T⁻³ projects a relative orbital space t² — an instance of T² (spatial anteriority) at the nuclear reference frame. Electrons exist as T⁻⁵ structures within t².

The atom is a fractal instance of the ArXe hierarchy: the same levels that govern cosmological structure (T⁻³, T², T⁻⁵) operate at the atomic scale within the nuclear reference frame.

2.3 Complete atomic map

ArXe component Atomic manifestation
T⁰ Contradictory ground state
T⁻³/T⁻²/T⁻¹ Nuclear structure
T² projection Orbital space t²
BC closed Stable electron configurations
BC open Reactive configurations
T⁻⁵ Electron (EM field level)
(n+l) Ontological depth in t²

3. Layer 1: Orbital Capacities from Aridity Correspondence

3.1 The exact correspondence

Each orbital type’s magnetic quantum number count (2l+1) corresponds exactly to the aridity of the ArXe negative levels:

Orbital l 2l+1 ArXe level Aridity Meaning
s 0 1 base minimal coupling
p 1 3 T⁻¹ 3 temporal alternation
d 2 5 T⁻² 5 spatial curvature
f 3 7 T⁻³ 7 color/mass variation

This is exact, not approximate. The number of magnetic states in each orbital is the aridity of the level that T⁻⁵ couples to.

The interpretation: an orbital is T⁻⁵ (the electron) coupled to a specific level of the ArXe hierarchy. The magnetic quantum states are the phases of that level’s indecidability — the number of ways the coupling can be oriented. When T⁻⁵ couples to T⁻¹ (aridity 3), there are exactly 3 orientations — the 3 magnetic states of the p orbital.

3.2 The spin factor

The factor 2 in cap = 2×(2l+1) is spin — the binary alternation of T⁻¹ as the most fundamental open BC. Every electron carries this binary indecidability as its irreducible structural property.

cap = 2 × (2l+1)
    = spin (T⁻¹ binary alternation) × magnetic states (aridity of coupled level)

3.3 Madelung order as probability order

⚠ Superseded (2026-07-30): the probability-based account below was retracted in arxe_periodic_table_paper_v2_en.md §4.4, which attributes the filling order to energy (differential nuclear phase access) rather than to coupling probability. The retraction was documented independently in arxe_statistical_manifestation_clarification_es.md (March 2026), which shows the s-orbital is actually the least frequent factorization of T⁻⁵ (1/11!) — the opposite of the probability argument below. This section is kept for historical/structural reference; the magnetic-quantum-number correspondence in §3.1–3.2 is not affected.

The filling order — s before p before d before f — was proposed to be exactly the order of decreasing coupling probability:

s: base coupling             → most probable
p: T⁻⁵ × T⁻¹ (aridity 3)  → P ~ 1/3! = 1/6     ≈ 0.167
d: T⁻⁵ × T⁻²  (aridity 5)  → P ~ 1/5! = 1/120   ≈ 0.008
f: T⁻⁵ × T⁻³ (aridity 7)  → P ~ 1/7! = 1/5040  ≈ 0.0002

Electrons fill s orbitals first not because of a rule imposed from outside, but because s orbitals are the most probable configuration available. The Madelung rule is the statistical manifestation of the principle that physical reality tends toward the most probable configurations — the most factored and lowest-aridity couplings.

3.4 Period lengths

Each period corresponds to all couplings available at depth n in the hierarchy:

Period n length = Σ 2×(2l+1) for l = 0 to n-1 = 2n²

The period lengths 2, 8, 18, 32… are the count of all ArXe couplings at each depth, weighted by the binary spin factor of T⁻¹.

3.5 The g orbital prediction

If the pattern continues, the g orbital (l=4) would couple to a level with aridity 2l+1 = 9 = 3².

But 9 is not an arity number. In the ArXe framework, levels whose aridity is not an arity number do not generate irreducible ontological operators — they are composite structures. This predicts that g orbitals do not correspond to a fundamental ArXe level, and therefore g-orbital elements should show structural instability.

Empirically: g orbitals are predicted to begin filling around element 121 (not yet synthesized). No stable g-orbital element exists. The ArXe framework predicts this is not merely an experimental limitation but a structural one: g orbitals involve a non-arity number aridity coupling (9 = 3²) that is fundamentally less stable than the arity-aridity couplings of s, p, d, and f.


4. Layer 2: Ontological Depth and Orbital Energies

4.1 The (n+l) sum as ontological depth

The Madelung ordering quantity (n+l) encodes the total ontological depth of the orbital in t²:

(n+l) Factorization ArXe reading Orbital group
1 pre-structural 1s
2 2 (DIFF) binary differentiation 2s
3 3 (CYC) ternary cycle — π enters 2p, 3s
4 2² (DIFF²) quaternary simultaneity 3p, 4s
5 5 (MEM) memory/persistence 3d, 4p, 5s
6 2×3 (OBJ) objective measurement 4d, 5p, 6s
7 7 (CPX) heptadic complexity 4f, 5d, 6p, 7s
8 2³ (EXP) triple spatial expansion 5f, 6d, 7p

All (n+l) values from 2 to 8 are ArXe-pure factorizations. This is a structural fact about small integers, not a fitting — small integers factorize into small arities, which are exactly the ArXe operators.

4.2 Orbital energies in Planck units

Hydrogen orbital energies in Planck units have ArXe-coherent arity number factorizations:

Orbital E/E_P (scaled) Factorization ArXe reading
1s 111 3×37 = CYC×TOP ground state: cycle + topological coherence
2s 279 3²×31 = CYC²×CHA double cycle + stable irregularity (radial node)
3s 124 2²×31 = DIFF²×CHA double differentiation + irregularity
4s 697 17×41 = SPEC×ISO spectral hierarchy + isolation (fills before 3d)
6s 31 31 = CHA pure irregularity (lanthanide region)

5 of 7 principal orbitals have ArXe-coherent readings. The 4s reading is particularly notable: SPEC×ISO (spectral separation × maximum isolation) encodes exactly the property that makes 4s fill before 3d — the most famous feature of the Madelung rule.

Status: These are coherent readings, not derivations. The factorizations are real but the interpretation requires that the ALO operators genuinely describe the orbital’s physical character — which is plausible but not formally derived.

4.3 The f orbital and color confinement

The f orbital (l=3) couples to T⁻³ — the same level that governs color confinement in QCD. The 7 magnetic states of the f orbital are the 7 phases of T⁻³.

This may explain why lanthanide and actinide elements (with f orbital electrons) have anomalous properties: their electronic structure is coupled to the same ontological level as quarks. The unusual magnetic properties, lanthanide contraction, and complex oxidation state chemistry of f-block elements may reflect T⁻³ structure operating at atomic scale.

Status: Exploratory. The correspondence is exact (aridity 7 = T⁻³ = f orbital) but the chemical consequences are not formally derived.


5. Layer 3: Exceptions at Z-Arity Thresholds

5.1 The observation

The major Madelung exceptions occur at element numbers Z that are ArXe arities:

Exception Z ArXe arity Operator Configuration
Copper 29 VBG Vacuum background 3d¹⁰ 4s¹
Niobium 41 ISO Maximum isolation 4d⁴ 5s¹
Silver 47 NEXT Next-phase threshold 4d¹⁰ 5s¹
Gold 79 CPV CP asymmetry 5d¹⁰ 6s¹

Additionally, the only two elements with Z < 83 and no stable isotopes are at Z-arity number positions:

  • Technetium Z=43 (TRANS — always transitioning)
  • Promethium Z=61 (DECAY — decay operator)

5.2 The proposed mechanism

When the element number Z is an ArXe arity, the element sits at an ontological threshold where the corresponding level operator influences the orbital filling. The d-shell completes preferentially because the level operator drives closure at that specific Z.

This would mean that Madelung exceptions are not arbitrary computational artifacts of exchange energy calculations — they are structurally necessary at the Z values where the atomic number itself carries an ArXe operator.

5.3 Predictions from Z-Arity structure

P1: Element Z=119 is not an ArXe arity (119 = 7×17 = CPX×SPEC). It will follow Madelung’s rule normally (8s¹ configuration expected), with no exceptional behavior driven by Z-Arity structure.

P2: Element Z=127 is an ArXe arity (HIER_1). It will show exceptional orbital filling behavior — the specific configuration cannot be predicted without knowing the 8s/7p/6d/5g energy competition, but the fact of exceptionality is predicted.

P3: Element Z=137 carries the fine structure constant’s reciprocal (α⁻¹ ≈ 137). If Z=137 is synthesized, its chemistry should show extraordinary electromagnetic sensitivity — this is the element where the EM level operator (arity 11, T⁻⁵) appears directly in the atomic number through the relation 137 = 11²−7²+5×13.

5.4 Honest assessment of Layer 3

The Z-arity number correspondence is structurally motivated and the predictions are testable. However, the mechanism — why Z being an ArXe arity should influence orbital filling — is proposed, not derived. A formal derivation would need to show how the nuclear charge Z couples to the ArXe level structure in a way that produces orbital exceptions at arity number Z values.

Until that derivation exists, Layer 3 should be read as a well-motivated prediction rather than a result.


6. Summary

Claim Status Evidence
(2l+1) = aridity of coupled ArXe level Confirmed — exact Exact numerical correspondence
Madelung order = probability order Confirmed — structural Combinatorial argument from aridity
Period lengths = 2n² from aridity Confirmed — derived Count of couplings at depth n
g orbital instability (aridity 9=3²) Prediction Non-arity number aridity → no fundamental level
(n+l) = ontological depth in t² Coherent All (n+l) values ArXe-pure factorizations
Orbital energies in Planck units Coherent — 5/7 ArXe-pure for principal orbitals
f orbital couples to T⁻³ (color) Exact — exploratory Aridity 7, chemical consequences not derived
Exceptions at Z-arity number thresholds Exploratory Motivated, mechanism not derived
Z=119 follows Madelung normally Prediction Z=119 = 7×17, not an arity number
Z=127 shows exceptional behavior Prediction Z=127 is ArXe arity

7. The Deeper Reading

The electronic structure of atoms is not an independent fact about chemistry. It is the manifestation of the ArXe hierarchy of levels in the specific context of T⁻⁵ (the electron) coupling to the levels available within the nuclear reference frame t².

The atom is the most directly testable instance of the ArXe framework: every element is a specific combination of ArXe level couplings, with its properties determined by which couplings are available and how probable they are.

The periodic table is not a catalog of substances. It is a record of which ArXe couplings are accessible at each level of nuclear charge — organized in order of decreasing probability, with structural thresholds at the arity number Z values where the atomic number itself carries an ontological operator.


For the primary ArXe framework: arxe_1_core_theory_V3_en.md
For the ALO grammar: Grammar_V4_Pure_en.md
For the probability principle: physics-as-statistical-manifestation.md
For the hierarchy chain of inversions: arxe_core_V4_221_en.md §4.4 (“The Hierarchy as a Chain of Inversions”)
For the corrected (energy-based) filling-order account: arxe_periodic_table_paper_v2_en.md §4.4