"Ionization energies of the elements in eV"
"1st IE/eV","2nd IE/eV"
"H",13.60,
"He",24.59,54.42
"Li",5.39,76.64
"Be",9.32,18.21
"B",8.30,25.15
"C",11.26,24.38
"N",14.53,29.60
"O",13.62,35.12
"F",17.97,34.97
"Ne",21.56,40.96
"Na",5.14,47.29
"Mg",7.65,15.04
"Al",5.99,18.83
"Si",8.15,16.35
"P",10.49,30.18
"S",10.36,23.33
"Cl",12.97,23.81
"Ar",15.76,27.63
"K",4.34,31.63
"Ca",6.11,11.87
"Sc",6.54,12.80
"Ti",6.82,13.58
"V",6.74,14.65
"Cr",6.77,16.50
"Mn",7.44,15.64
"Fe",7.87,16.18
"Co",7.86,17.06
"Ni",7.64,18.17
"Cu",7.73,20.29
"Zn",9.39,17.96
"Ga",6.00,20.51
"Ge",7.90,15.93
"As",9.81,18.63
"Se",9.75,21.19
"Br",11.81,21.80
"Kr",14.00,24.36
