The chemical symbol for Cesium is Cs and its atomic number is 55.
We find it listed in the periodic table of elements in group 1 and period 6 and block s.
Cesium belongs to the family or chemical series of alkali metals such as for example the Francium, Lithium, Potassium, ..This element is stable, Cesium came from caesius.
Atomic number (Z) 55
Group, block group 1 (alkali metals), s-block
Period: period 6
Element category: alkali metal
Standard atomic weight (±) (Ar): 132.90545196(6)[1]
Electron configuration: [Xe] 6s1
per shell: 2, 8, 18, 18, 8, 1
Physical properties:
Phase: solid
Melting point: 301.7 K (28.5 °C, 83.3 °F)
Boiling point: 944 K (671 °C, 1240 °F)
Density near r.t.: 1.93 g/cm3
when liquid, at m.p. 1.843 g/cm3
Critical point: 1938 K, 9.4 MPa[2]
Heat of fusion: 2.09 kJ/mol
Heat of vapourisation: 63.9 kJ/mol
Molar heat capacity : 32.210 J/(mol•K)
Atomic properties
Oxidation states: +1, −1
Electronegativity: Pauling scale: 0.79
Ionisation energies: 1st: 375.7 kJ/mol
2nd: 2234.3 kJ/mol
3rd: 3400 kJ/mol
Atomic radius empirical: 265 pm
Covalent radius: 244±11 pm
Van der Waals radius: 343 pm
Crystal structure: body-centered cubic
Thermal expansion: 97 µm/(m•K) (at 25 °C)
Thermal conductivity: 35.9 W/(m•K)
Electrical resistivity: 205 nΩ•m (at 20 °C)