55 Cs 132.905
Cesium
alkali metal
Properties
- Atomic number
- 55
- Atomic mass
- 132.905 u
- Category
- alkali metal
- Group
- 1
- Period
- 6
- Block
- s-block
- State (room temp)
- Solid
- Outer-shell electrons
- 1
- Electronegativity
- 0.79 (Pauling)
- Density
- 1.93 g/cm³
- Melting point
- 28.55 °C
- Boiling point
- 670.85 °C
Electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s¹
Noble-gas shorthand: [Xe] 6s¹
Electrons per shell: 2, 8, 18, 18, 8, 1, which is 1 in the outermost shell.
Related: electron configuration, the Bohr model, valence electrons.
About Cesium
Caesium 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.
- Discovered by Robert Bunsen
- Appearance: silvery gold
Cesium: frequently asked questions
- What is Cesium?
- Cesium (Cs) is the chemical element with atomic number 55. It is a metal: specifically an alkali metal.
- What is the atomic number of Cesium?
- Cesium's atomic number is 55, which means every Cesium atom has 55 protons in its nucleus.
- What is the electron configuration of Cesium?
- The electron configuration of Cesium is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s1 (noble-gas shorthand: [Xe] 6s1). Its electrons are arranged in shells of 2, 8, 18, 18, 8, 1, with 1 in the outermost shell.
- Is Cesium a metal or a nonmetal?
- Cesium is a metal: specifically an alkali metal.
- What group and period is Cesium in?
- Cesium is in group 1 and period 6 of the periodic table.
- Is Cesium a solid, liquid, or gas?
- At room temperature, Cesium is a solid.
Position in the periodic table
Data compiled from Wikipedia, PubChem, and IUPAC. Source.