Potassium (K) - Element 19 | Properties & Electron Configuration

What is Potassium?

Potassium (K) is element 19, a alkali metal in period 4, group 1. Its electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹.

Atomic Number19
SymbolK
Atomic Mass39.098 u
CategoryAlkali Metal
Period4
Group1
Blocks
Electron Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
Short Config[Ar] 4s¹
Electronegativity0.82
Atomic Radius220 pm
Ionization Energy419 kJ/mol
Electron Affinity48 kJ/mol
Phase (STP)Solid

Electron Configuration

The full electron configuration of Potassium is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹. In noble gas shorthand, this is written as [Ar] 4s¹.

Potassium is a s-block element in group 1, period 4.

Periodic Trends

Electronegativity: Potassium has a Pauling electronegativity of 0.82. Within group 1, electronegativity generally decreases down the group.

Atomic Radius: 220 pm. Across period 4, atomic radius generally decreases left to right as nuclear charge increases.

Ionization Energy: 419 kJ/mol. Ionization energy generally increases across a period and decreases down a group.

View all 118 elements with trend overlays for electronegativity, atomic radius, ionization energy, and electron affinity.

Explore Potassium on the Interactive Periodic Table

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