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19K39.098
Potassium
Alkali MetalPotassium is a chemical element with symbol K (derived from Neo-Latin, kalium) and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name is derived. In the Periodic table, potassium is one of seven elements in column (group) 1 (alkali metals):they all have a single valence electron in their outer electron shell, which they readily give up to create an atom with a positive charge - a cation, and combine with anions to form salts.
Phase: SolidAppearance: silvery gray
2, 8, 8, 1
Physical Properties
Atomic Mass39.09831 u
Density0.862 g/cm³
Melting Point336.7 K
Boiling Point1032 K
Molar Heat29.6 J/(mol·K)
Period4
PhaseSolid
Chemical Properties
Electron Configuration1s2 2s2 2p6 3s2 3p6 4s1
Semantic Config[Ar] 4s1
Shells2, 8, 8, 1
Electron Affinity48.383 kJ/mol
Electronegativity0.82
Ionization Energies
IE1: 418.8 kJ/molIE2: 3052 kJ/molIE3: 4420 kJ/molIE4: 5877 kJ/molIE5: 7975 kJ/molIE6: 9590 kJ/molIE7: 11343 kJ/molIE8: 14944 kJ/molIE9: 16963.7 kJ/molIE10: 48610 kJ/molIE11: 54490 kJ/molIE12: 60730 kJ/molIE13: 68950 kJ/molIE14: 75900 kJ/molIE15: 83080 kJ/molIE16: 93400 kJ/molIE17: 99710 kJ/molIE18: 444880 kJ/molIE19: 476063 kJ/mol
Discovery
Discovered byHumphry Davy