Potassium

Chemical, physical and material properties and data of the chemical element Potassium.

Contents

General Information about Potassium

Regular namePotassiumChemical symbolKOther namesHistorical namesName meaning, originDiscovery (year)OccurencePosition in the PSEGroup membership

Atomar Properties of Potassium

Atomic number Z19 = number of protonsStandard Atomic Weight39.0983 (1)

Electron configuration of Potassium

1s	2s	2p	3s	3p	3d	4s	4p	4d	4f	5s	5p	5d	5f	6s	6p	6d	6f	7s	7p
2	2	6	2	6		1

Shorthand electron configuration of Potassium: [Ar] 4s¹ .

Ionization Energies of Potassium

The following table lists the ionization energies IE (ionization potentials); the IE is the energy required in electron volt (eV) per atom to separate a given electron from an Potassium atom.

IE1	IE2	IE3	IE4	IE5	IE6	IE7	IE8
4.3406633	31.63	45.806	60.91	82.66	99.4	117.56	154.88

Isotopic Data of Potassium

An overview of the nuclides as well as the isotopic data and properties are listed on the following page: Potassium isotopes.

Chemistry of Potassium

Oxidation states+1Electronegativity0.8 (Pauling original)
0.82 (Pauling)
0.734 (Allen)
1.1 (Mulliken)
0.74 (Sanderson)
0.91 (Allred-Rochow)
2.0027 eV (Gosh Gupta)
2.42 eV (Pearson)Electron affinity0.501 459(13) eV
48.383(2) kJ mol^-1

Standard Electrode Potential

E⁰ (V)	Symbol	N_ox	Name Ox. Name Red.	Ox. Red.	e^-
-2.931	K	+ I 0	Potassium cation Potassium	K⁺ ⇄ K (s)	+ e^-

Material and Physical Properties

Melting point63.38 °CEnthalpy of fusion (molar)2.321 kJ mol^-1Boiling point759 °CEnthalpy of vaporization77.53 kJ mol^-1Density0.862 g cm^-3

External Data, Identifiers

CAS registry number7440-09-7InChI =1S/KInChIKeyZLMJMSJWJFRBEC-UHFFFAOYSA-NPubChem ID5462222

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isotopes

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Last update: 2022-12-12

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