Electron Configuration

Interactive simulation — adjust parameters and watch the visualization update in real time.

Aufbau prediction

1s²2/2 e⁻

2s²2/2 e⁻

2p⁶6/6 e⁻

3s²2/2 e⁻

3p⁴4/6 e⁻

Reference (periodic dataset)

1s²2/2 e⁻

2s²2/2 e⁻

2p⁶6/6 e⁻

3s²2/2 e⁻

3p⁴4/6 e⁻

Compact notation

1s2 2s2 2p6 3s2 3p4

Sulfur or sulphur (see spelling differences) is a chemical element with symbol S and atomic number 16. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8.

How it works

**Aufbau** filling (Klechkowski order) predicts how subshells fill with increasing **Z**. Many ground-state atoms follow it, but **exceptions** (Cr, Cu, Mo, Pd, …) lower the energy by promoting one **s** electron into **d** or **f**. The **reference** row uses curated configurations from the periodic dataset.

Key equations

Order: 1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p → …