Potassium (symbol K, atomic number 19) is a reactive alkali metal essential to nerve function and a major fertiliser nutrient. It is classified as a alkali metal and sits in group 1, period 4 of the periodic table.
Overview
Potassium is the chemical element with atomic number 19 and the symbol K. With a standard atomic weight of 39.098, it is a alkali metal. In the periodic table it occupies group 1 and period 4, and under standard conditions it is normally a solid. Potassium is a reactive alkali metal essential to nerve function and a major fertiliser nutrient.
Atomic structure
An atom of Potassium has 19 protons in its nucleus and, when neutral, 19 electrons arranged in the configuration [Ar] 4s1. Its standard atomic weight of 39.098 reflects the natural mix of its stable isotopes.
Discovery and place in the table
Potassium was discovered in 1807 by Humphry Davy. It follows Argon (Ar) and precedes Calcium (Ca) in order of atomic number.
| Atomic number | 19 |
|---|---|
| Symbol | K |
| Atomic mass | 39.098 |
| Category | Alkali metal |
| Group | 1 |
| Period | 4 |
| Electron configuration | [Ar] 4s1 |
| Phase at STP | Solid |
| Discovered | 1807 (Humphry Davy) |