Template:Infobox potassium

Potassium,  ₁₉K

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General properties
Pronunciation	Template:Infobox element/pronunciation
Appearance	silvery gray
Standard atomic weight (Ar, standard)	Template:Infobox element/standard atomic weight
Mass number	Template:Infobox element/symbol-to-most-stable-isotope (most stable isotope)
Potassium in the periodic table
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Atomic number (Z)	19
Group	Template:Infobox element/group
Period	period 4
Block	s-block
Element category	Template:Infobox element/category format
Electron configuration	[Ar] 4s1
Electrons per shell	2, 8, 8, 1
Physical properties
Phase at STP	solid
Melting point	336.7 K ​(63.5 °C, ​146.3 °F)
Boiling point	1032 K ​(759 °C, ​1398 °F)
Density (near r.t.)	0.862 g/cm3
when liquid (at m.p.)	0.828 g/cm3
Critical point	2223 K, 16 MPa
Heat of fusion	2.33 kJ/mol
[[Enthalpy of vaporization|Heat of Template:Engvar]]	76.9 kJ/mol
Molar heat capacity	29.6 J/(mol·K)
Atomic properties
Oxidation states	Template:Infobox element/symbol-to-oxidation-state
Electronegativity	Pauling scale: 0.82
[[Ionization energy|Template:Engvar energies]]	1st: 418.8 kJ/mol 2nd: 3052 kJ/mol 3rd: 4420 kJ/mol (more)
Atomic radius	empirical: 227 pm
Covalent radius	203±12 pm
Van der Waals radius	275 pm
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Other properties
Crystal structure	​Template:Infobox element/crystal structure Template:Infobox element/crystal structure
Speed of sound thin rod	2000 m/s (at 20 °C)
Thermal expansion	83.3 µm/(m·K) (at 25 °C)
Thermal conductivity	102.5 W/(m·K)
Electrical resistivity	72 nΩ·m (at 20 °C)
Magnetic ordering	paramagnetic
Magnetic susceptibility	+20.8·10−6 cm3/mol (298 K)
Young's modulus	3.53 GPa
Shear modulus	1.3 GPa
Bulk modulus	3.1 GPa
Mohs hardness	0.4
Brinell hardness	0.363 MPa
CAS Number	7440-09-7
History
Discovery and first isolation	Humphry Davy (1807)
Main isotopes of potassium
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Template:Infobox element/element navigation Template:Template reference list One of these is a named reference. It may be cited in the containing article as

• <ref name="CIAAW2016" /> for the source Atomic weights of the elements 2013 (from subtemplates used by {{Infobox element}})