Lithium Electron Configuration

Explore lithium's electron configuration (1s2 2s1), orbital filling diagram, and key atomic properties in one place.

Full Electron Configuration

1s2 · 2s1

Lithium has 3 electrons. The first 2 fill the 1s subshell completely, and the remaining 1 electron occupies the 2s subshell. Subshells are filled following the Aufbau principle in order of increasing energy.

Core electrons
2
Valence electrons
1

Atomic Properties

3 Li Lithium
Period: 2
Group: 1 (Alkali Metals)
Block: s-block
State (25°C): Solid
Atomic Number (Z) 3
Atomic Mass 6.941 u
Electron Config. 1s² 2s¹
Valence Electrons 1
Electronegativity 0.98 (Pauling)
1st Ionization Energy 520.2 kJ/mol
Atomic Radius 152 pm
Common Oxidation State +1

Electron Shell Diagram

Shell 1 (K): 2 electrons  |  Shell 2 (L): 1 electron

Summary

Explore lithium's electron configuration (1s2 2s1), orbital filling diagram, and key atomic properties in one place.

How it works

  1. Select the notation you want to view: full, shorthand, or orbital diagram.
  2. The full configuration (1s2 2s1) shows each subshell filled in order.
  3. The shorthand uses the preceding noble gas [He] to condense the notation.
  4. The orbital diagram shows each orbital as a box with spin-up/spin-down arrows.
  5. Key atomic properties — atomic number, mass, period, group, valence electrons — are displayed in the reference panel.

Use cases

  • Quick reference for lithium electron configuration during chemistry coursework.
  • Visualizing subshell filling order with the orbital box diagram.
  • Understanding why lithium is in Group 1 (one valence electron in 2s).
  • Comparing full vs. noble-gas shorthand notation.
  • Reviewing periodic table properties for element 3.
  • Studying ionization energy trends and reactivity of alkali metals.

Frequently Asked Questions

Last updated: 2026-06-18 · Reviewed by Nham Vu