View source for Data:First ionization energies of the elements

{{see|Ionization energy}}
Data are taken from the [[wavenumber]] compilation of Moore (1970) unless otherwise noted, and converted using the 2006 [[CODATA recommended value]]s:<ref>{{CODATA 2006}}.</ref><ref group="Note">Moore used the conversion factor 1&nbsp;cm<sup>−1</sup>&nbsp;= {{nowrap|0.000 123 981 eV}}, which is 26&nbsp;ppm lower than the current value. Moore's value in [[electronvolt]]s are widely reprinted without correction.</ref>
: 1 cm<sup>−1</sup> = 0.000 123 984 1875(31) eV = 0.011 903 713 931(12) kJ mol<sup>−1</sup>

{| class="wikitable sortable"
|-
! rowspan=2 | [[Atomic number|''Z'']]
! rowspan=2 | Element
! colspan=2 | [[Ionization energy]]
! rowspan=2 | Ref.
|-
! (eV)
! (kJ mol<sup>−1</sup>)
|-
| 1
| [[Hydrogen]]
| 13.598 432 44(36)
| 1305.584 631(12)
| 
|-
| 2
| [[Helium]]
| 24.587 3985(14)
| 2360.634 56(12)
| 
|-
| 3
| [[Lithium]]
| 5.391 718 96(64)
| 517.658 593(60)
| 
|-
| 4
| [[Beryllium]]
| 9.322 6277(13)
| 895.064 89(12)
| 
|-
| 5
| [[Boron]]
| 8.298 024(18)
| 800.6377(17)
| <ref>{{citation | first1 = B. | last1 = Edlén | first2 = A. | last2 = Ölme | first3 = G. | last3 = Herzberg | first4 = J. W. C. | last4 = Johns | title = Ionization Potential of Boron, and the Isotopic and Fine Structure of 2s2p<sup>2</sup> <sup>2</sup>''D'' | journal = J. Opt. Soc. Am. | volume = 60 | issue = 7 | pages = 889–91 | year = 1970 | doi = 10.1364/JOSA.60.000889}}.</ref><ref>{{citation | last1 = Brown | first1 = C. M. | last2 = Tilford | first2 = S. G. | last3 = Ginter | first3 = M. L. | title = Absorption spectrum of B&nbsp;I in the 1350–1900-Å region | journal = J. Opt. Soc. Am. | year = 1974 | volume = 64 | issue = 6 | pages = 877–79 | doi = 10.1364/JOSA.64.000877}}.</ref>
|-
| 6
| [[Carbon]]
| 11.260 296(12)
| 796.6930(12)
| 
|-
| 7
| [[Nitrogen]]
| 14.534 096(12)
| 1395.4176(12)
| 
|-
| 8
| [[Oxygen]]
| 13.618 0537(74)
| 1307.468 47(71)
| 
|-
| 9
| [[Fluorine]]
| 17.422 816(50)
| 1672.7634(48)
| 
|-
| 10
| [[Neon]]
| 
| 
| <ref group="Note" name="useMoore">The results from Moore (1970) were also used in evaluating the weighted mean.</ref>
|-
| 89
| [[Actinium]]
| 5.3807(3)
| 
| <ref>{{citation | last1 = Backe | first1 = H. | last2 = Dretzke | first2 = A. | last3 = Eberhardt | first3 = K. | last4 = Fritzsche | first4 = S. | last5 = Kube | first5 = G. | last6 = Gwinner | first6 = G. | last7 = Haire | first7 = R. G. | last8 = Huber | first8 = G. | last9 = Waldek | first9 = A. | title = First Determination of the Ionization Potential of Actinium and First Observation of Optical Transitions in Fermium | journal = J. Nucl. Sci. Technol. | year = 2002 | pages = 86–89}}.</ref>
|-
| 90
| [[Thorium]]
| 6.3067(2)
| 
| <ref name="Köhler">{{citation | first1 = S. | last1 = Köhler | first2 = R. | last2 = Deißenberger | first3 = K. | last3 = Eberhardt | first4 = N. | last4 = Erdmann | first5 = G. | last5 = Herrmann | first6 = G. | last6 = Huber | first7 = J. V. | last7 = Kratz | first8 = M. | last8 = Nunnemann | first9 = G. | last9 = Passler | first10 = P. M. | last10 = Rao | first11 = J. | last11 = Riegel | first12 = N. | last12 = Trautmann | first13 = K. | last13 = Wendt | title = Determination of the first ionization potential of actinide elements by resonance ionization mass spectroscopy | journal = Spectrochim. Acta, Part B | volume = 52 | issue = 6 | year = 1997 | pages = 717–26 | doi = 10.1016/S0584-8547(96)01670-9}}.</ref>
|-
|}

==Notes==
{{reflist|group=Note}}

==References==
{{NSRDS-NBS 34}}.
{{reflist}}

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