Potassium
Potassium (钾, symbol K) is chemical element number 19, an Alkali Metal in period 4, group 1 of the periodic table, with a standard atomic weight of about 39.098. Soft silvery metal, vital for nerve and muscle function. Found in bananas, potatoes, and salts.
Properties
| Atomic number | 19 |
|---|---|
| Symbol | K |
| Atomic mass | 39.098 u |
| Category | Alkali Metal |
| Period | 4 |
| Group | 1 |
| Electron configuration | [Ar] 4s¹ |
| Electronegativity | 0.82 |
| Covalent radius | 203 pm |
| Density | 0.862 g/cm³ |
| Melting point | 336.53 K |
| Boiling point | 1032 K |
| Discovery | Humphry Davy, 1807 |
Overview
Soft silvery metal, vital for nerve and muscle function. Found in bananas, potatoes, and salts. Potassium (K) holds position 19 in the periodic table, an Alkali Metal in period 4, group 1. As an alkali metal it is soft and highly reactive, releasing hydrogen on contact with water, and is usually stored away from air and moisture.
With 1 electron in its outermost shell, Potassium bonds accordingly; full configuration [Ar] 4s¹, electronegativity 0.82. At room temperature it is normally a solid (a very low melting point); it melts near 336.53 K (63.4 °C), boils near 1032 K (758.9 °C), has a density around 0.862 g/cm³.
Common applications range across Agriculture / Fertiliser and Medical / Pharma. Compounds featured on this site include KOH. On the safety side, it carries a moderate hazard rating. It was first described by Humphry Davy in 1807. The periodic trends guide explains the underlying patterns.
Electron shells
Electrons per shell: 2 · 8 · 8 · 1
Main uses
- Agriculture / Fertiliser
- Medical / Pharma
Hazard
Compounds containing Potassium
Data sources
Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.