Electronic Configuration of First 18 Elements

The arrangement or distribution of electrons in the shells and sub-shells of an atom is called its electronic configuration.

Hydrogen (H) — Atomic No. 1 — 1s¹ 

Helium (He) — Atomic No. 2 — 1s² 

Lithium (Li) — Atomic No. 3 — 1s² 2s¹ 

Beryllium (Be) — Atomic No. 4 — 1s² 2s² 

Boron (B) — Atomic No. 5 — 1s² 2s² 2p¹ 

Carbon (C) — Atomic No. 6 — 1s² 2s² 2p² 

Nitrogen (N) — Atomic No. 7 — 1s² 2s² 2p³ 

Oxygen (O) — Atomic No. 8 — 1s² 2s² 2p⁴ 

Fluorine (F) — Atomic No. 9 — 1s² 2s² 2p⁵ 

Neon (Ne) — Atomic No. 10 — 1s² 2s² 2p⁶ 

Sodium (Na) — Atomic No. 11 — 1s² 2s² 2p⁶ 3s¹ 

Magnesium (Mg) — Atomic No. 12 — 1s² 2s² 2p⁶ 3s² 

Aluminum (Al) — Atomic No. 13 — 1s² 2s² 2p⁶ 3s² 3p¹ 

Silicon (Si) — Atomic No. 14 — 1s² 2s² 2p⁶ 3s² 3p²

Phosphorous (P) — Atomic No. 15 — 1s² 2s² 2p⁶ 3s² 3p³

Sulphur (S) — Atomic No. 16 — 1s² 2s² 2p⁶ 3s² 3p⁴ 

Chlorine (Cl) — Atomic No. 17 — 1s² 2s² 2p⁶ 3s² 3p⁵

Argon (Ar) — Atomic No. 18 — 1s² 2s² 2p⁶ 3s² 3p⁶