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Compare Hydrogen vs Potassium

Comparing Hydrogen (H) and Potassium (K). Atomic numbers 1 and 19 with atomic masses 1.008 u and 39.098 u, classified as nonmetal and alkali metal. 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
H
Hydrogen
#1
K
Potassium
#19

Periodic properties of the elements

HydrogenPotassium
SymbolHK
Atomic number119
Group11
Period14
Blockss
Element categoryNonmetalAlkali Metal

Physical properties

HydrogenPotassium
Phase at STPGasSolid
Density0.08988 g/cm30.862 g/cm3
Atomic weight1.0079 u39.0983 u
Melting point13.99 K
-259.16 °C
-434.488 °F		336.7 K
63.55 °C
146.39 °F
Boiling point20.271 K
-252.879 °C
-423.1822 °F		1032 K
758.85 °C
1397.93 °F

Atomic properties

HydrogenPotassium
Electronegativity (Pauling Scale)2.20.82
Electron affinity72.769 kJ/mol48.383 kJ/mol
Oxidation states−1, +1
(an amphoteric oxide)		−1, +1
(a strongly basic oxide)
Ionization energies
  1. 1312 kJ/mol
  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

Electron configuration

HydrogenPotassium
Shorthand configuration1s1 [Ar] 4s1
Full configuration1s1 1s2 2s2 2p6 3s2 3p6 4s1
Electrons per shell12, 8, 8, 1

History

HydrogenPotassium
DiscoveryHenry Cavendish (1766)Humphry Davy (1807)
First isolationHenry Cavendish (1766)Humphry Davy (1807)
Named byAntoine Lavoisier (1783)
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