What is the electron configuration of sulfur?

Sulfur (S, Z=16) has the ground-state electron configuration 1s² 2s² 2p⁶ 3s² 3p⁴. Its 16 electrons fill five subshells across three principal shells.

What is the noble-gas shorthand for sulfur?

The condensed (noble-gas) notation is [Ne] 3s² 3p⁴, where [Ne] represents the filled 1s² 2s² 2p⁶ core shared with neon.

How many valence electrons does sulfur have?

Sulfur has 6 valence electrons: 2 in the 3s subshell and 4 in the 3p subshell. This is why sulfur sits in Group 16 (VIA).

Why does sulfur commonly form S²⁻?

Sulfur gains 2 electrons to complete its 3p subshell (reaching 3p⁶), achieving the stable argon [Ar] noble-gas configuration. This produces the sulfide ion S²⁻.

What are the common oxidation states of sulfur?

Sulfur shows oxidation states of −2 (H₂S, sulfides), +4 (SO₂), and +6 (SO₃, H₂SO₄). Its ability to use d-orbital involvement at higher energies allows the expanded valence states +4 and +6.

What block and period is sulfur in?

Sulfur is in Period 3, Group 16 (VIA), and belongs to the p-block of the periodic table. Its last electron fills the 3p subshell.

How does Hund's rule apply to sulfur's 3p electrons?

The 3p subshell has three orbitals. Hund's rule requires that each orbital receives one electron before any pairing occurs. Sulfur's 4 electrons in 3p fill as: first orbital paired (↑↓), second orbital spin-up (↑), third orbital spin-up (↑) — giving 2 unpaired electrons.

Sulfur Electron Configuration

Name: Sulfur Electron Configuration
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Interactive reference for sulfur's electron configuration (1s² 2s² 2p⁶ 3s² 3p⁴), orbital box diagram, quantum numbers, and key atomic properties.

Z = 16 S Sulfur

Sulfur — Electron Configuration

Atomic number 16 · Nonmetal · Period 3, Group 16 · p-block

1s² 2s² 2p⁶ 3s² 3p⁴ [Ne] 3s² 3p⁴ 16 electrons 6 valence e⁻

Subshell Breakdown

Subshell	Type	Electrons	Max Capacity	Notation
1s	s orbital, shell n=1	2	2	1s²
2s	s orbital, shell n=2	2	2	2s²
2p	p orbitals, shell n=2	6	6	2p⁶
3s	s orbital, shell n=3	2	2	3s²
3p	p orbitals, shell n=3	4	6	3p⁴
Total		16

Full Configuration

1s² 2s² 2p⁶ 3s² 3p⁴

All subshells written explicitly.

Noble-Gas Shorthand

[Ne] 3s² 3p⁴

[Ne] = 1s² 2s² 2p⁶ (the filled neon core).

Shell Fill Summary

Shell 1 (n=1) — 1s² 2 / 2 electrons (100%)

Shell 2 (n=2) — 2s² 2p⁶ 8 / 8 electrons (100%)

Shell 3 (n=3) — 3s² 3p⁴ 6 / 18 electrons (33%)

Shell 3 can hold up to 18 electrons (3s + 3p + 3d). Sulfur uses 6 of those 18 slots. Two more electrons would fill 3p and produce the argon configuration.

Orbital Box Diagram

2 electrons (paired) — filled

6 electrons across 3 orbitals — filled

2 electrons (paired) — filled

4 electrons: 1 pair + 2 unpaired (Hund's rule) — valence shell

Each box represents one orbital. Opposing arrows represent paired electrons (+½ and −½ spins). Hund's rule requires one electron in each p orbital before any pairing — sulfur's 3p⁴ leaves 2 unpaired electrons and 2 paired.

Quantum Numbers for All 16 Electrons

Electron #	n	l	mₗ	mₛ	Subshell
1	1	0	0	+½	1s
2	1	0	0	−½	1s
3	2	0	0	+½	2s
4	2	0	0	−½	2s
5	2	1	-1	+½	2p
6	2	1	-1	−½	2p
7	2	1	0	+½	2p
8	2	1	0	−½	2p
9	2	1	1	+½	2p
10	2	1	1	−½	2p
11	3	0	0	+½	3s
12	3	0	0	−½	3s
13	3	1	-1	+½	3p
14	3	1	-1	−½	3p
15	3	1	0	+½	3p
16	3	1	1	+½	3p

n = principal quantum number; l = azimuthal (l=0 → s, l=1 → p); mₗ = magnetic; mₛ = spin. Electrons 15 and 16 in 3p share mₗ = 0 and +1 as their first singly occupied orbitals per Hund's rule before pairing.

Summary

Interactive reference for sulfur's electron configuration (1s² 2s² 2p⁶ 3s² 3p⁴), orbital box diagram, quantum numbers, and key atomic properties.

How it works

The Aufbau principle fills orbitals from lowest to highest energy.
Sulfur's 16 electrons occupy five subshells: 1s, 2s, 2p, 3s, and 3p.
The 2p subshell holds 6 electrons across three orbitals, all fully paired.
The 3p subshell holds 4 electrons: two orbitals are paired and one orbital holds a single spin-up electron, then a second orbital holds a single electron — Hund's rule dictates singly filling before pairing.
Noble-gas notation replaces the inner filled [Ne] core (1s² 2s² 2p⁶) with brackets: [Ne] 3s² 3p⁴.
Sulfur has 6 valence electrons (3s² 3p⁴), which explains its common −2 and +4/+6 oxidation states.

Use cases

Quick reference for chemistry homework or exam review on Period 3 elements.
Visualize orbital filling and Hund's rule for the partially filled 3p subshell.
Understand why sulfur forms S²⁻ (gains 2 electrons to fill 3p) or S⁶⁺ (loses all valence electrons).
Compare sulfur to its Group 16 neighbors oxygen and selenium.
Teaching aid for introductory atomic structure, VSEPR, and Lewis structure lessons.
Verify quantum numbers for each of sulfur's 16 electrons.
Understand how the 3p⁴ configuration drives sulfur's varied bonding in SO₂, SO₃, and H₂S.
Support work on oxidation states and electronegativity trends across Period 3.

Frequently Asked Questions

Last updated: 2026-07-08 · Reviewed by Nham Vu