• Class: Alkalis
• Period: 4
• IUPAC group: 1
• Traditional: Ia

• Discovered in: 1807 by Davy
• Origin of name: English, potash also Kalium
• Historical or alternate name: Kalium

Sylvite, carnallite, langbeinite, polyhalite & potash

Soft, white metal. Fresh surface has silvery sheen. Quickly forms dull oxide coating on exposure to air. Reacts strongly with water.

• Atmosphere: ~0.0 ppm
• Primitive mantle: 180.0 ppm
• Sea water: 380 ppm
• Metallic meteorite: 5.69 ppm
• Continental crust: 9100.0 ppm
• Solar photosphere: 5.16 log of abundance
• Oceanic crust: 1250.0 ppm
• Solar system: 3770.0 relative to Si=1.0e6

   Hazards

Reacts with water to give off flammable gas. Reacts violently with oxidants..

• Lower:Required
• Upper:

Potassium Physical Properties

 Transitional Data

• State: Solid
• Density: 0.86 g/cm3

 Molar enthalpy

• Atomization: 90.14 kJ mol-1
• Fusion: 2.40 kJ mol-1
• Vaporization: 79.1 kJ mol-1

 Transition points

• Melting point: 336.40 K
• Boiling point: 1033.0 K
• Critical temperature: 2223.0 K

 Molar properties

• Atomic weight: 39.0983 g/mole
• Molar volume: 45.646 cm3 mol-1

 Crystal structure sequence

body-centered-cubic

 Thermodynamics

• State: solid
  • Enthalpy 0
  • Gibbs function 0
  • Entropy 64.18
  • Heat Capacity 29.58

• State: gas
  • Enthalpy 89.24
  • Gibbs function 60.59
  • Entropy 160.336
  • Heat Capacity 20.786

 Miscellaneous physical

• Electrical resistivity: 6.15 µ-ohms/cm
• Debye temperature: 91.0 K
• Thermal conductivity: 102.0 W / m / K
• Coefficient of linear expansion: 83.0Coef. per K
• Mass magnetic susceptibility: 6.7e-9
• X-ray diffraction mass absorption coefficients:
• CuK: 143 (µ/p)/cm2 g-1
• MoK: 15.8 (µ/p)/cm2 g-1

Potassium Chemical Properties

 Chemical basics:

• Oxidation states: +1
• Molecular wt: 39.0983 g/mole

 Radii

• Covalent: 203 pm
• Atomic: 235.0 pm
• Van der Waals: 231 pm

 Ions:

• ion: +1pm 138.0

 Covalent bonds

 Effective nuclear charge

• Slater: 2.20
• Clementi: 3.50
• Froese-Fischer: 4.58

 Electronegativity

• Pauling: 0.8
• Allred-Rochow: 0.91

 Standard reactions

Potassium Nuclear Properties

• Known 10
• Listed 3

• Known 37 - 45
• Listed 39 - 41

• % Occ.:Natural 93.2581%
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 3/2
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 0.0117%
• Mossbauer NRA: 4.726
• Nuclear spin/Quantum no.: 4/0
• Radioisotopes:
  • Half-life: 1.25 E9 years
  • Decay mode: Beta- E.C., Beta+
  • Source:
• Notes date med

• % Occ.:Natural 6.7302%
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 3/2
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• Isotope Cross-section 2.2±0.2 barns

• Absolute sensitivity: 4.73e-4 1H=1.0
• Relative sensitivity: 5.08e-4 1H=1.0
• Receptivity: 2.69 13C=1.0
• Magnetogyric ratio: 1.2483e7 rad / T / s
• Quadropole moment: 5.5e-30 m2
• Frequency: 4.667 MHz
• Reference: K+

Potassium Energy Properties

Electrons

• Ground state electron configuration: [Ar] 4s1
• Electron affinity: 48.3 kJ mol-1
• Filling orbitals:

Spectral lines

 Ionization energies

 Atomic energy levels