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Compare Potassium vs Hydrogen

Comparing Potassium (K) and Hydrogen (H). Atomic numbers 19 and 1 with atomic masses 39.098 u and 1.008 u, classified as alkali metal and nonmetal. Below: a side-by-side comparison of their physical, atomic, electron-configuration and historical properties, including density, melting and boiling points, ionization energies, oxidation states and discovery history.

vs
K
Potassium
#19
H
Hydrogen
#1

Periodic properties of the elements

PotassiumHydrogen
SymbolKH
Atomic number191
Group11
Period41
Blockss
Element categoryAlkali MetalNonmetal

Physical properties

PotassiumHydrogen
Phase at STPSolidGas
Density0.862 g/cm30.08988 g/cm3
Atomic weight39.0983 u1.0079 u
Melting point336.7 K
63.55 °C
146.39 °F		13.99 K
-259.16 °C
-434.488 °F
Boiling point1032 K
758.85 °C
1397.93 °F		20.271 K
-252.879 °C
-423.1822 °F

Atomic properties

PotassiumHydrogen
Electronegativity (Pauling Scale)0.822.2
Electron affinity48.383 kJ/mol72.769 kJ/mol
Oxidation states−1, +1
(a strongly basic oxide)		−1, +1
(an amphoteric oxide)
Ionization energies
  1. 418.8 kJ/mol
  2. 3052 kJ/mol
  3. 4420 kJ/mol
  4. 5877 kJ/mol
  5. 7975 kJ/mol
  6. 9590 kJ/mol
  7. 11343 kJ/mol
  8. 14944 kJ/mol
  9. 16963.7 kJ/mol
  10. 48610 kJ/mol
  11. 54490 kJ/mol
  12. 60730 kJ/mol
  13. 68950 kJ/mol
  14. 75900 kJ/mol
  15. 83080 kJ/mol
  16. 93400 kJ/mol
  17. 99710 kJ/mol
  18. 444880 kJ/mol
  19. 476063 kJ/mol
  1. 1312 kJ/mol

Electron configuration

PotassiumHydrogen
Shorthand configuration[Ar] 4s1 1s1
Full configuration1s2 2s2 2p6 3s2 3p6 4s1 1s1
Electrons per shell2, 8, 8, 11

History

PotassiumHydrogen
DiscoveryHumphry Davy (1807)Henry Cavendish (1766)
First isolationHumphry Davy (1807)Henry Cavendish (1766)
Named byAntoine Lavoisier (1783)
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