K
Potassium
Potassium is a chemical element with the symbol K and atomic number 19. It has a standard atomic weight of 39.098, sits in period 4 and group 1, and is classified as an alkali metal.
Properties
| Symbol | K |
|---|---|
| Atomic number | 19 |
| Standard atomic weight | 39.098 |
| Category | Alkali metal |
| Group | 1 |
| Period | 4 |
| Electron configuration | [Ar] 4s1 |
| Outer-shell electrons | 1 |
The figure of 39.098 is a standard atomic weight.
Compounds containing potassium
14 of the compounds in this reference contain K, listed by the fraction of their mass it makes up.
| Compound | Formula | Atoms | % by mass |
|---|---|---|---|
| potassium hydroxide | HKO | 1 | 69.7% |
| potassium cyanide | CKN | 1 | 60.0% |
| potassium carbonate | CK2O3 | 2 | 56.6% |
| potassium chloride | ClK | 1 | 52.4% |
| potassium ferrocyanide | C6FeK4N6 | 4 | 42.5% |
| potassium nitrate | KNO3 | 1 | 38.7% |
| potassium ferricyanide | C6FeK3N6 | 3 | 35.6% |
| potassium chlorate | ClKO3 | 1 | 31.9% |
| potassium phosphate | H2KO4P | 1 | 28.7% |
| potassium dichromate | Cr2K2O7 | 2 | 26.6% |
| potassium permanganate | KMnO4 | 1 | 24.7% |
| potassium iodide | IK | 1 | 23.6% |
| potassium bromate | BrKO3 | 1 | 23.4% |
| potassium iodate | IKO3 | 1 | 18.3% |
Calculate with potassium
- Molar mass of any formula containing it
- Electron configuration, including ions
- Effective nuclear charge by Slater's rules
- Average atomic mass from isotope abundances
Group 1
Atomic weights are the IUPAC 2021 standard values, abridged to the conventional five significant figures. Group, period, category and electron configuration are derived from the atomic number rather than stored, so they cannot drift out of step with it.