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Atomic: M.A.C. | Reference
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Potassium
Electrons per shell 2,8,8,1
Electron Configuration [Ar] 4s1 open electron config
Ground state 2S1/2
Atomic Volume 45.46 cm3 mol-1
Electronegativity 0.82
Magnetic ordering No data
Mass magnetic susceptibility 6.7 x 10-9
Molar magnetic susceptibility 2.62 x 10-10
Speed of sound 2000 m s-1
Thermal Properties
Enthalpy of Atomization 89.5 kJ mol-1 @25°C
Enthalpy of Fusion 2.40 kJ mol-1
Enthalpy of Vaporisation 79.1 kJ mol-1
Heat Capacity 29.600 J mol-1 K-1
Thermal Conductivity 102.5 W m-1 K-1
Thermal Expansion 83.3 μm m-1 K-1
Hardness
Brinell hardness 0.363 MPa
Mohs hardness 0.4
Elastic Properties
Bulk modulus 3.1 GPa
Shear modulus 1.3 GPa
Electrical Properties
Electrical resistivity 7 x 10-8 Ω m
Electrical conductivity 0.139 106/cm Ω
Chemical Properties
Electrochemical Equivalent 1.4587 g Ah-1
Electron Work Function 2.3 eV
Valence Electron Potential (-eV) 10.4
Ionization Potential  
First 4.341
Second 31.625
Third 45.72
Energy Levels
Kα1 (intensity 100) 3.3138 KeV
Kα2 (intensity 0) 3.3111 KeV
Kβ1 (intensity 13.7) 3.5896 KeV
Lα1 (intensity 100) 0.2591 KeV
Lγ3 (intensity 0) 0.262 KeV
Ll (intensity 100) 0.2591 KeV
Atomic Radii
Empirical 220 pm
Bohr Radius 243 pm
Covalent Radius 196 pm
Van der Waals 275 pm
Triple covalent No data.
Metallic 227 pm
Oxidation States
Main K+1
Other K-1 (in liquid NH3)
Ionisation Energies (kJ mol-1) show graph
M - M+ 418.8
M+ - M2+ 3051.4
M2+ - M3+ 4411
M3+ - M4+ 5877
M4+ - M5+ 7975
M5+ - M6+ 9649
M6+ - M7+ 11343
M7+ - M8+ 11942
M8+ - M9+ 16964
M9+ - M10+ 48575
Crystal Structure
Structure Body centred cubic
a = 532.8 pm
b = 532.8 pm
c = 532.8 pm
α = 90°
β = 90°
γ = 90°