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Caesium
Block sPeriod 6Group 1solid at 20 °C
Configuration :[Xe] 6s¹
Atomic mass :132.90545196 u
French :Césium
3D Bohr-model representation of the Caesium atom (symbol Cs, atomic number Z=55). Electron shell configuration: 2, 8, 18, 18, 8, 1 electrons.
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Bohr model · educational
Electron configuration
Full[Xe] 6s¹
Short[Xe] 6s¹
Valence electrons1
KLMNOPQ shells
K2
L8
M18
N18
O8
P1
Electronegativity
Pauling0.79
Allen0.659
Mulliken (eV)—
Atomic radii
Empirical260 pm
Calculated298 pm
Covalent244 pm
Van der Waals343 pm
Ionic radii (Shannon-Prewitt)
+1167 pm
Successive ionisation energies
I₁375.7 kJ/mol
I₂2234.3 kJ/mol
I₃3400 kJ/mol
Electron affinity45.5 kJ/mol
Oxidation states
-1+1
Bold states = most common.