| From Wikipedia, the free encyclopediaCaesium or cesium is a chemical element with symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a melting point of 28 °C (82 °F), which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium is an alkali metal and has physical and chemical properties similar to those of rubidium and potassium. | |||||||
Cesium in the periodic table | |||||||
|---|---|---|---|---|---|---|---|
| Symbol | Cs | ||||||
| Atomic number | 55 | ||||||
| Group | 1 | ||||||
| Period | 6 | ||||||
| Block | s | ||||||
| Element category | Alkali Metal | ||||||
Physical properties | |||||||
| Phase at STP | Solid | ||||||
| Density | 1.93 g/cm3 | ||||||
| Atomic weight | 132.905 u | ||||||
| Melting point | 301.7 K 28.55 °C 83.39 °F | ||||||
| Boiling point | 944 K 670.85 °C 1239.53 °F | ||||||
Atomära egenskaper | |||||||
| Electronegativity (Pauling Scale) | 0.79 | ||||||
| Electron affinity | 45.505 kJ/mol | ||||||
| Ionization energies |
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Electron configuration | |||||||
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 6s1 | ||||||
| Electrons per shell | 2, 8, 18, 18, 8, 1 | ||||||
History | |||||||
| Discovered | 1860 | ||||||
| Discovered by | Robert Bunsen Gustav Kirchhoff | ||||||