Electron Configuration of Potassium (K)

What is the electron configuration of Potassium?

The electron configuration of Potassium (K, Z=19) is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹. In noble gas shorthand: [Ar] 4s¹. It has 1 unpaired electron(s) and is a s-block element.

SymbolK
Atomic Number19
Full Electron Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
Noble Gas Shorthand[Ar] 4s¹
Blocks
Period4
Group1
Unpaired Electrons1
Exception?No

Orbital Filling Order

Following the aufbau principle, the 19 electrons in Potassium fill orbitals in order of increasing energy: 1s (2 electrons), then 2s (2 electrons), then 2p (6 electrons), then 3s (2 electrons), then 3p (6 electrons), then 4s (1 electron).

Each orbital is filled according to the Pauli exclusion principle (at most 2 electrons per orbital) and Hund's rule (electrons occupy degenerate orbitals singly before pairing).

Noble Gas Shorthand

The inner electrons of Potassium match the configuration of Ar. This allows us to abbreviate the configuration as [Ar] 4s¹, where [Ar] represents the filled core and the remaining entries show the valence electrons.

Valence Electrons

The valence shell of Potassium contains 1 electron in the 4s subshell. These outermost electrons determine Potassium's chemical reactivity, bonding behavior, and position in the periodic table as a s-block element in period 4.

Visualize orbital filling with 3D orbital shapes, aufbau principle, and noble gas shorthand for 36 elements.

Explore Potassium in the Electron Configuration Explorer

Related Topics

Electron Configuration of Calcium

Orbital filling and noble gas shorthand for Calcium

Electron Configuration of Scandium

Orbital filling and noble gas shorthand for Scandium

Electron Configuration of Hydrogen

Orbital filling for Hydrogen (s-block)

Electron Configuration of Helium

Orbital filling for Helium (s-block)

Potassium on the Periodic Table

Full properties and periodic trends for Potassium

Orbital Hybridization

See how atomic orbitals mix to form sp, sp2, and sp3 hybrids