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%I #16 Oct 23 2018 05:49:57
%S 1312,2372,520,900,801,1087,1402,1314,1681,2081,496,738,578,787,1012,
%T 1000,1251,1521,419,590,633,659,651,653,717,763,760,737,746,906,579,
%U 762,947,941,1140,1351,403,550,600,640,652,684,702,710,720,804,731,868,558,709,834,869,1008,1170,376,503,538,534,527,533,540,545,547,593,566,573,581,589,597,603,524,659,761,770,760,840,880,870,890,1007,589,716,703,812,899,1037,380,509,499,587,568,598,605,585,578,581,601,608,619,627,635,642,470,580
%N First ionization energy (in kJ/mol) of the chemical elements, rounded to the nearest integer.
%C The first ionization energy of an element X is the enthalpy change of X (g) -> X+ (g) + e-.
%C The values for chemical elements in each period (1 - 2, 3 - 10, 11 - 18, 19 - 36, 37 - 54, 55 - 86) are overall increasing, with boron group elements (boron, aluminum, gallium, indium, thallium) having relative low first ionization energies comparing with their nearby elements.
%H NIST Atomic Spectra Database, <a href="https://physics.nist.gov/PhysRefData/ASD/ionEnergy.html">Ionization Energies Form</a>
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Ionization_energies_of_the_elements_(data_page)">Ionization energies of the elements (data page)</a>
%e The first ionization energies for hydrogen (1), helium (2) and lithium (3), etc. are 1312.0 kJ/mol, 2372.3 kJ/mol, 520.2 kJ/mol, etc.
%Y Cf. A320507.
%K nonn,look
%O 1,1
%A _Jianing Song_, Oct 13 2018