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Compare Sodium vs Cesium

Comparing Sodium (Na) and Cesium (Cs). Atomic numbers 11 and 55 with atomic masses 22.99 u and 132.905 u, classified as alkali metal and alkali metal. Below: a side-by-side comparison of their physical, atomic, electron-configuration and historical properties, including density, melting and boiling points, ionization energies, oxidation states and discovery history.

vs
Na
Sodium
#11
Cs
Cesium
#55

Periodic properties of the elements

SodiumCesium
SymbolNaCs
Atomic number1155
Group11
Period36
Blockss
Element categoryAlkali MetalAlkali Metal

Physical properties

SodiumCesium
Phase at STPSolidSolid
Density0.968 g/cm31.93 g/cm3
Atomic weight22.9898 u132.905 u
Melting point370.944 K
97.794 °C
208.0292 °F		301.7 K
28.55 °C
83.39 °F
Boiling point1156.09 K
882.94 °C
1621.292 °F		944 K
670.85 °C
1239.53 °F

Atomic properties

SodiumCesium
Electronegativity (Pauling Scale)0.930.79
Electron affinity52.867 kJ/mol45.505 kJ/mol
Oxidation states−1, +1
(a strongly basic oxide)		−1, +1
(a strongly basic oxide)
Ionization energies
  1. 495.8 kJ/mol
  2. 4562 kJ/mol
  3. 6910.3 kJ/mol
  4. 9543 kJ/mol
  5. 13354 kJ/mol
  6. 16613 kJ/mol
  7. 20117 kJ/mol
  8. 25496 kJ/mol
  9. 28932 kJ/mol
  10. 141362 kJ/mol
  11. 159076 kJ/mol
  1. 375.7 kJ/mol
  2. 2234.3 kJ/mol
  3. 3400 kJ/mol

Electron configuration

SodiumCesium
Shorthand configuration[Ne] 3s1 [Xe] 6s1
Full configuration1s2 2s2 2p6 3s1 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 6s1
Electrons per shell2, 8, 12, 8, 18, 18, 8, 1

History

SodiumCesium
DiscoveryHumphry Davy (1807)Robert Bunsen, Gustav Kirchhoff (1860)
First isolationHumphry Davy (1807)Carl Setterberg (1882)
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