Ionization Energies (kJ/mole)
Z
1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th
1 H 1312









2 He 2372 5251








3 Li 520 7298 11815







4 Be 900 1757 14849 21007






5 B 801 2427 3660 25026 32828





6 C 1086 2353 4621 6223 37832 47278




7 N 1402 2856 4578 7475 9445 53268 64362



8 O 1314 3388 5301 7469 10989 13327 71337 84080


9 F 1681 3374 6051 8408 11022 15164 17868 92040 106437

10 Ne 2081 3952 6122 9370 12177 15239 19999 23069 115382 131435
11 Na 496 4563 6913 9544 13352 16611 20115 25491 28934 141367 159179
12 Mg 738 1451 7733 10541 13629 17995 21704 25657 31644 35463 169996
13 Al 578 1817 2745 11578 14831 18378 23296 27460 31862 38458 42655
14 Si 789 1577 3232 4356 16091 19785 23787 29253 33878 38734 45935
15 P 1012 1903 2912 4957 6274 21269 25398 29855 35868 40960 46274
16 S 1000 2251 3361 4564 7012 8496 27107 31671 36579 43140 48706
17 Cl 1251 2297 3822 5158 6542 9362 11018 33606 38601 43963 51068
18 Ar 1521 2666 3931 5771 7238 8781 11996 13842 40761 46188 52003
19 K 419 3051 4412 5877 7975 9469 11343 14942 16964 48577 54433
20 Ca 590 1145 4912 6474 8144 10496 12320 14207 18192 20385 57050
21 Sc 631 1235 2389 7089 8844 10720 13320 15313 17370 21741 24106
22 Ti 658 1310 2653 4175 9573 11517 13586 16259 18640 20833 25592
23 V 650 1414 2828 4507 6294 12362 14490 16760 19860 22240 24609
24 Cr 653 1592 2987 4740 6686 8738 15540 17822 20200 23580 26130
25 Mn 717 1509 3249 4940 6985 9200 11508 18956 21400 23960 27600
26 Fe 759 1561 2958 5290 7236 9600 12100 14576 22679 25290 28020
27 Co 758 1646 3232 4950 7671 9840 12400 15100 17960 26600 29400
28 Ni 737 1753 3394 5300 7285 10400 12800 15600 18600 21660 30990
29 Cu 746 1958 3554 5330 7709 9940 13400 16000 19200 22400 25700
30 Zn 906 1733 3833 5730 7970 10400 12900 16800 19600 23000 26400
31 Ga 579 1979 2963 6200






32 Ge 762 1537 3302 4411 9021





33 As 947 1798 2736 4837 6043 12312




34 Se 941 2045 2974 4144 6590 7883 14990



35 Br 1140 2100 3500 4560 5760 8549 9938 18600


36 Kr 1351 2368 3565 5070 6243 7574 10710 12158 22230

37 Rb 403 2632 3900 5080 6850 8144 9572 13100 14500 26740
38 Sr 550 1064 4210 5500 6908 8761 10200 11800 15600 17100 31270
Z
1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th
39 Y 616 1181 1980 5960 7429 8973 11200 12400 14137 18400 19900
40 Zr 660 1267 2218 3313 7863 9500




41 Nb 664 1382 2416 3700 4877 9900 12100



42 Mo 685 1558 2621 4480 5905 6600 12230 14800


43 Tc 702 1472 2850







44 Ru 711 1617 2747







45 Rh 720 1745 2997







46 Pd 805 1875 3177







47 Ag 731 2074 3361







48 Cd 868 1631 3613







49 In 558 1821 2705 5200






50 Sn 709 1412 2943 3930 6974





51 Sb 834 1595 2440 4260 5403 10400




52 Te 869 1790 2698 3610 5668 6820 13200



53 I 1008 1846 3200 16400






54 Xe 1170 2047 3100







55 Cs 376 2420 3300







56 Ba 503 965








57 La 538 1067 1850 4820






63 Eu 547 1085 2404 4110






72 Hf 680 1440 2250 3215






73 Ta 761









74 W 770 1700








75 Re 760 1600








76 Os 840 1600








77 Ir 880









78 Pt 870 1791








79 Au 890 1980








80 Hg 1007 1810 3300







81 Tl 589 1971 2878 4900






82 Pb 716 1450 3082 4083 6639





83 Bi 703 1610 2466 4370 5403 8500




84 Po 812









86 Rn 1037