Cesium (Cs) — Element 55: Properties & Data | Aladdin Scientific
Cesium(Cs) — Element 55
Cesium (Cs) is a alkali metal with atomic number 55 and atomic mass 132.905. It has melting point 301.59 K (28 °C), boiling point 944 K (671 °C), density 1.93 g/cm³. It sits in group 1 and period 6 of the periodic table and was discovered in 1860.
Key facts
| Atomic mass | 132.9055 u |
|---|---|
| Electron configuration | [Xe]6s1 |
| Oxidation states | +1 |
| Electronegativity (Pauling) | 0.79 |
| Atomic radius (van der Waals) | 343 pm |
| Ionization energy | 3.894 eV |
| Electron affinity | 0.472 eV |
| Melting point | 301.59 K |
| Boiling point | 944 K |
| Density | 1.93 g/cm³ |
| Standard state | Solid |
| Year discovered | 1860 |
Frequently asked questions
What is the electron configuration of cesium?
The ground-state electron configuration of cesium is [Xe]6s1.
What group and period is cesium in?
Cesium (Cs) is in group 1 and period 6 of the periodic table, classified as a alkali metal.
What is the melting point of cesium?
Cesium melts at 301.59 K (28 °C).
What is the standard state of cesium?
Cesium is a solid at standard temperature and pressure.
Related elements
About this data: property values compiled from IUPAC Standard Atomic Weights (2021), the NIST Atomic Spectra Database, and PubChem. Curated by the Aladdin Scientific technical team. Last reviewed: .