Atomic number 19
Potassium
Alkali metal
In the real world
Quick facts
- Atomic mass
- 39.098
- Group
- 1
- Period
- 4
- State (STP)
- solid
- Electronegativity
- 0.82
- Common ox. states
- +1
Properties
Electron configuration
[Ar] 4s¹
- Ionization energy
- 418.8 kJ/mol
- Electron affinity
- 48.4 kJ/mol
- Melting point
- 336.70 K (63.6 °C)
- Boiling point
- 1032.00 K (758.9 °C)
How dangerous is it?
4/5 · Severe
A soft metal even more eager to react than sodium. Drop it in water and it skitters around, bursts into a lilac flame, and can pop.
- FlammableImmediate
The heat ignites the hydrogen at once, often with a small explosion.
A potassium fire is smothered with dry sand, never water.
- ReactiveImmediate
It reacts with water faster than sodium, releasing hydrogen and a lot of heat.
Stored under oil and handled dry; never let near water.
How it bonds
Potassium loses its 4s electron even more easily than sodium does (lower IE, higher up the reactivity series). K⁺ is the dominant intracellular cation in your nerve cells - every action potential is K⁺ moving across a membrane.
Where you meet it
- Periodic Quest challengeunlock card
