Jaconir
Quantum Physics Engine

ELECTRON STRUCTURE
& ORBITAL VIEWER

d-block
Fe
Iron
ATOMIC NUMBER Z = 26

Aufbau Exceptions

Our database includes exact configurations for transition metals like Cr, Cu, Ag, and Au that deviate from standard subshell filling.

Configuration Analysis
Noble Gas Shorthand
[Ar] 4s2 3d6
Principal Shells (K, L, M)
n=1: 2
n=2: 8
n=3: 14
n=4: 2
Last Subshell filling
3d6
Differentiating
Orbital Box Diagram

Hund's Rule & Pauli Exclusion Principle

m=0
1s2
m=0
2s2
m=-2
m=-1
m=0
2p6
m=0
3s2
m=-2
m=-1
m=0
3p6
m=0
4s2
m=-4
m=-3
m=-2
m=-1
m=0
3d6

Principal (n)

3

Energy Level

Azimuthal (l)

2

Subshell (d)

Magnetic (ml)

-2

Orientation

Spin (ms)

-1/2

Rotation

Atomic Theory Reference

QUANTUM MECHANICS
IN THE BROWSER

"If you think you understand quantum mechanics, you don't understand quantum mechanics." — Richard Feynman. Our tool simplifies the math so you can focus on the physics.

1
Aufbau Principle

Electrons always occupy the lowest available energy orbital first (1s < 2s < 2p).

2
Pauli Exclusion

No two electrons can have identical sets of quantum numbers; orbitals hold max 2 electrons with opposite spins.

3
Hund's Rule

Orbitals of the same subshell are first occupied singly by electrons with fixed spins.

EXPLAINER & FAQ

Q. How are quantum numbers derived?

Each electron is a wave function solution. We solve for the 'n', 'l', 'ml', and 'ms' integers that define that electron's specific probability cloud.

Q. What about Cr and Cu exceptions?

To minimize energy, atoms like Chromium prefer half-filled subshells (4s1 3d5) instead of standard filling (4s2 3d4).

Q. What is a differentiating electron?

It is the last electron added to an atom to complete its configuration relative to the element with one fewer proton.

Jaconir Scientific Tool • 2026 Edition