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Compare Calcium vs Radium

Comparing Calcium (Ca) and Radium (Ra). Atomic numbers 20 and 88 with atomic masses 40.078 u and 226 u, classified as alkaline earth metal and alkaline earth 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
Ca
Calcium
#20
Ra
Radium
#88

Periodic properties of the elements

CalciumRadium
SymbolCaRa
Atomic number2088
Group22
Period47
Blockds
Element categoryAlkaline Earth MetalAlkaline Earth Metal

Physical properties

CalciumRadium
Phase at STPSolidSolid
Density1.55 g/cm35.5 g/cm3
Atomic weight40.0784 u226 u
Melting point1115 K
841.85 °C
1547.33 °F		1233 K
959.85 °C
1759.73 °F
Boiling point1757 K
1483.85 °C
2702.93 °F		2010 K
1736.85 °C
3158.33 °F

Atomic properties

CalciumRadium
Electronegativity (Pauling Scale)10.9
Electron affinity2.37 kJ/mol9.6485 kJ/mol
Oxidation states+1, +2
(a strongly basic oxide)		+2
(expected to have a strongly basic oxide)
Ionization energies
  1. 589.8 kJ/mol
  2. 1145.4 kJ/mol
  3. 4912.4 kJ/mol
  4. 6491 kJ/mol
  5. 8153 kJ/mol
  6. 10496 kJ/mol
  7. 12270 kJ/mol
  8. 14206 kJ/mol
  9. 18191 kJ/mol
  10. 20385 kJ/mol
  11. 57110 kJ/mol
  12. 63410 kJ/mol
  13. 70110 kJ/mol
  14. 78890 kJ/mol
  15. 86310 kJ/mol
  16. 94000 kJ/mol
  17. 104900 kJ/mol
  18. 111711 kJ/mol
  19. 494850 kJ/mol
  20. 527762 kJ/mol
  1. 509.3 kJ/mol
  2. 979 kJ/mol

Electron configuration

CalciumRadium
Shorthand configuration[Ar] 4s2 [Rn] 7s2
Full configuration1s2 2s2 2p6 3s2 3p6 4s2 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p6 7s2
Electrons per shell2, 8, 8, 22, 8, 18, 32, 18, 8, 2

History

CalciumRadium
DiscoveryHumphry Davy (1808)Pierre Curie, Marie Curie (1898)
First isolationHumphry Davy (1808)Marie Curie (1910)
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