K
Potassium is an essential alkali metal vital for nerve and muscle function.
Physical Properties
| Atomic Mass | 39.098 u |
| Density | 0.862 g/cm³ |
| Melting Point | 336.53 K |
| Boiling Point | 1032.0 K |
| Appearance | Silvery-white metallic |
| State at Room Temp | Solid |
Chemical Properties
| Electronegativity | 0.82 (Pauling) |
| 1st Ionization Energy | 418.8 kJ/mol |
| Electron Affinity | 48.4 kJ/mol |
| Oxidation States | +1 |
Atomic Properties
| Electron Configuration | [Ar] 4s1 |
| Atomic Radius | 227.0 pm |
| Covalent Radius | 203.0 pm |
| Van der Waals Radius | 275.0 pm |
Discovery
| Discovered By | Humphry Davy |
| Discovery Year | 1807 |
| Location | London, England |
| Named After | English 'potash'; symbol K from Latin 'kalium' |
About Potassium
Potassium is a soft, silvery-white metal that reacts vigorously with water. It is essential for all living cells, playing a critical role in nerve transmission, muscle contraction, and fluid balance. It was the first metal isolated by electrolysis.
Uses & Applications
Fertilizers (potash), soap, gunpowder, glass manufacturing, food preservation, and medical IV fluids.
Fun Fact
Bananas are famously associated with potassium, but avocados and spinach actually contain more per serving.
Isotopes
| Mass Number | Abundance | Half-Life | Stable |
| 39 | 0.932581% | - | Yes |
| 40 | 0.000117% | 1.248 billion years | No |
| 41 | 0.067302% | - | Yes |
Electron Configuration
[Ar] 4s1