P

Potassium

IUPAC: Potassium

K Elements CAS 7440-09-7
Quick Reference
Formula / NotationK
CAS Number7440-09-7
Molecular Weight39.1
Melting Point63.5
Boiling Point759.0
Density0.89
SolubilityReacts violently with water
AppearanceSoft, silvery-white metal, rapidly oxidises to grey
Also Known AsK, kalium, potassium metal
CategoryElements

What is Potassium?

Potassium is a soft, silvery-white alkali metal, atomic number 19. Highly reactive with water. Essential element for all living organisms - maintains cellular electrical potential and nerve function. Seventh most abundant element in Earth crust.

Formula & Notation

K

IUPAC Name: Potassium

Other Names / Synonyms: K, kalium, potassium metal

Properties & Characteristics

Atomic number: 19. Atomic mass: 39.098 g/mol. Period 4, Group 1. Melting point: 63.5 C. Boiling point: 759 C. Density: 0.89 g/cm3. Electronegativity: 0.82. Always +1 oxidation state. Violet/lilac flame test. Isotopes: K-39 (93.3%), K-40 (radioactive), K-41.

Physical Data

PropertyValue
Melting Point63.5
Boiling Point759.0
Density0.89
Molecular Weight39.1
SolubilityReacts violently with water
AppearanceSoft, silvery-white metal, rapidly oxidises to grey

Uses & Applications

Potassium hydroxide (KOH) production. Fertilisers (potassium chloride KCl, potassium sulfate). Potassium nitrate (gunpowder, fertiliser). Biological electrolyte (cardiac function). Potassium permanganate (KMnO4) oxidant. Soap making.

Safety Information

Reacts violently with water: 2K + 2H2O -> 2KOH + H2 (ignites H2 immediately). More reactive than sodium. Store under mineral oil. Causes severe chemical burns. Reacts with oxygen to form K2O2 (explosive with water). Handle with extreme care.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Potassium
Formula K
CAS Number 7440-09-7
Molecular Weight 39.1
Category Elements
Synonyms K, kalium, potassium metal

Frequently Asked Questions

Potassium is a soft, silvery-white alkali metal, atomic number 19. Highly reactive with water. Essential element for all living organisms - maintains cellular electrical potential and nerve function. Seventh most abundant element in Earth crust.

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