Input interpretation
s-block elements | first ionization energy
Summary
median | 514.7 kJ/mol highest | 2372.3 kJ/mol (helium) lowest | 375.7 kJ/mol (cesium) distribution |
Units
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Plot
Periodic table location
Periodic table location
Distribution plots
(first ionization energy in kilojoules per mole)
First ionization energy rankings
1 | cesium | 375.7 kJ/mol 2 | francium | 380 kJ/mol 3 | rubidium | 403 kJ/mol 4 | potassium | 418.8 kJ/mol 5 | sodium | 495.8 kJ/mol 6 | barium | 502.9 kJ/mol 7 | radium | 509.3 kJ/mol 8 | lithium | 520.2 kJ/mol 9 | strontium | 549.5 kJ/mol 10 | calcium | 589.8 kJ/mol 11 | magnesium | 737.7 kJ/mol 12 | beryllium | 899.5 kJ/mol 13 | hydrogen | 1312 kJ/mol 14 | helium | 2372.3 kJ/mol
Unit conversions for median first ionization energy 514.7 kJ/mol
0.5147 MJ/mol (megajoules per mole)
514700 J/mol (joules per mole)
123 kcal/mol (thermochemical kilocalories per mole)
5.335 eV (molar electronvolts)
Comparisons for median first ionization energy 514.7 kJ/mol
≈ ( 0.22 ≈ 1/5 ) × molar energy required to remove the first electron from helium ( 2372 kJ/mol )
≈ 1.4 × molar energy required to remove the first electron from cesium ( 377 kJ/mol )