Molar ionization energies of the elements

These tables list values of molar ionization energies, measured in kJ⋅mol⁻¹. This is the energy per mole necessary to remove electrons from gaseous atoms or atomic ions. The first molar ionization energy applies to the neutral atoms. The second, third, etc., molar ionization energy applies to the further removal of an electron from a singly, doubly, etc., charged ion. For ionization energies measured in the unit eV, see Ionization energies of the elements (data page). All data from rutherfordium onwards is predicted.

1st–10th ionization energies

{| class="wikitable sortable" style="font-size:90%;"

! Number !! Symbol !! Name

! 1st !! 2nd !! 3rd !! 4th !! 5th !! 6th !! 7th !! 8th !! 9th !! 10th

|-

| 1 || H || hydrogen

| <!--1st-->1312.0

|-

| 2 || He || helium

| <!--1st-->2372.3 || <!--2nd-->5250.5

|-

| 3 || Li || lithium

| <!--1st-->520.2 || <!--2nd-->7298.1 || <!--3rd-->11,815.0

|-

| 4 || Be || beryllium

| <!--1st-->899.5 || <!--2nd-->1757.1 || <!--3rd-->14,848.7 || <!--4th-->21,006.6

|-

| 5 || B || boron

| <!--1st-->800.6 || <!--2nd-->2427.1 || <!--3rd-->3659.7 || <!--4th-->25,025.8 || <!--5th-->32,826.7

|-

| 6 || C || carbon

| <!--1st-->1086.5 || <!--2nd-->2352.6 || <!--3rd-->4620.5 || <!--4th-->6222.7 || <!--5th-->37,831 || <!--6th-->47,277.0

|-

| 7 || N || nitrogen

| <!--1st-->1402.3 || <!--2nd-->2856 || <!--3rd-->4578.1 || <!--4th-->7475.0 || <!--5th-->9444.9 || <!--6th-->53,266.6 || <!--7th-->64,360

|-

| 8 || O || oxygen

| <!--1st-->1313.9 || <!--2nd-->3388.3 || <!--3rd-->5300.5 || <!--4th-->7469.2 || <!--5th-->10,989.5 || <!--6th-->13,326.5 || <!--7th-->71,330 || <!--8th-->84,078.0

|-

| 9 || F || fluorine

| <!--1st-->1681.0 || <!--2nd-->3374.2 || <!--3rd-->6050.4 || <!--4th-->8407.7 || <!--5th-->11,022.7 || <!--6th-->15,164.1 || <!--7th-->17,868 || <!--8th-->92,038.1 || <!--9th-->106,434.3

|-

| 10 || Ne || neon

| <!--1st-->2080.7 || <!--2nd-->3952.3|| <!--3rd-->6122 || <!--4th-->9371 || <!--5th-->12,177 || <!--6th-->15,238.90 || <!--7th-->19,999.0 || <!--8th-->23,069.5 || <!--9th-->115,379.5 || <!--10th-->131,432

|-

| 11 || Na || sodium

| <!--1st-->495.8 || <!--2nd-->4562 || <!--3rd-->6910.3 || <!--4th-->9543 || <!--5th-->13,354 || <!--6th-->16,613 || <!--7th-->20,117 || <!--8th-->25,496 || <!--9th-->28,932 || <!--10th-->141,362

|-

| 12 || Mg || magnesium

| <!--1st-->737.7 || <!--2nd-->1450.7 || <!--3rd-->7732.7 || <!--4th-->10,542.5 || <!--5th-->13,630 || <!--6th-->18,020 || <!--7th-->21,711 || <!--8th-->25,661 || <!--9th-->31,653 || <!--10th-->35,458

|-

| 13 || Al || aluminium

| <!--1st-->577.5 || <!--2nd-->1816.7 || <!--3rd-->2744.8 || <!--4th-->11,577 || <!--5th-->14,842 || <!--6th-->18,379 || <!--7th-->23,326 || <!--8th-->27,465 || <!--9th-->31,853 || <!--10th-->38,473

|-

| 14 || Si || silicon

| <!--1st-->786.5 || <!--2nd-->1577.1 || <!--3rd-->3231.6 || <!--4th-->4355.5 || <!--5th-->16,091 || <!--6th-->19,805 || <!--7th-->23,780 || <!--8th-->29,287 || <!--9th-->33,878 || <!--10th-->38,726

|-

| 15 || P || phosphorus

| <!--1st-->1011.8 || <!--2nd-->1907 || <!--3rd-->2914.1 || <!--4th-->4963.6 || <!--5th-->6273.9 || <!--6th-->21,267 || <!--7th-->25,431 || <!--8th-->29,872 || <!--9th-->35,905 || <!--10th-->40,950

|-

| 16 || S || sulfur

| <!--1st-->999.6 || <!--2nd-->2252 || <!--3rd-->3357 || <!--4th-->4556 || <!--5th-->7004.3 || <!--6th-->8495.8 || <!--7th-->27,107 || <!--8th-->31,719 || <!--9th-->36,621 || <!--10th-->43,177

|-

| 17 || Cl || chlorine

| <!--1st-->1251.2 || <!--2nd-->2298 || <!--3rd-->3822 || <!--4th-->5158.6 || <!--5th-->6542 || <!--6th-->9362 || <!--7th-->11,018 || <!--8th-->33,604 || <!--9th-->38,600 || <!--10th-->43,961

|-

| 18 || Ar || argon

| <!--1st-->1520.6 || <!--2nd-->2665.8 || <!--3rd-->3931 || <!--4th-->5771 || <!--5th-->7238 || <!--6th-->8781 || <!--7th-->11,995 || <!--8th-->13,842 || <!--9th-->40,760 || <!--10th-->46,186

|-

| 19 || K || potassium

| <!--1st-->418.8 || <!--2nd-->3052 || <!--3rd-->4420 || <!--4th-->5877 || <!--5th-->7975 || <!--6th-->9590 || <!--7th-->11,343 || <!--8th-->14,944 || <!--9th-->16,963.7 || <!--10th-->48,610

|-

| 20 || Ca || calcium

| <!--1st-->589.8 || <!--2nd-->1145.4 || <!--3rd-->4912.4 || <!--4th-->6491 || <!--5th-->8153 || <!--6th-->10,496 || <!--7th-->12,270 || <!--8th-->14,206 || <!--9th-->18,191 || <!--10th-->20,385

|-

| 21 || Sc || scandium

| <!--1st-->633.1 || <!--2nd-->1235.0 || <!--3rd-->2388.6 || <!--4th-->7090.6 || <!--5th-->8843 || <!--6th-->10,679 || <!--7th-->13,310 || <!--8th-->15,250 || <!--9th-->17,370 || <!--10th-->21,726

|-

| 22 || Ti || titanium

| <!--1st-->658.8 || <!--2nd-->1309.8 || <!--3rd-->2652.5 || <!--4th-->4174.6 || <!--5th-->9581 || <!--6th-->11,533 || <!--7th-->13,590 || <!--8th-->16,440 || <!--9th-->18,530 || <!--10th-->20,833

|-

| 23 || V || vanadium

| <!--1st-->650.9 || <!--2nd-->1414 || <!--3rd-->2830 || <!--4th-->4507 || <!--5th-->6298.7 || <!--6th-->12,363 || <!--7th-->14,530 || <!--8th-->16,730 || <!--9th-->19,860 || <!--10th-->22,240

|-

| 24 || Cr || chromium

| <!--1st-->652.9 || <!--2nd-->1590.6 || <!--3rd-->2987 || <!--4th-->4743 || <!--5th-->6702 || <!--6th-->8744.9 || <!--7th-->15,455 || <!--8th-->17,820 || <!--9th-->20,190 || <!--10th-->23,580

|-

| 25 || Mn || manganese

| <!--1st-->717.3 || <!--2nd-->1509.0 || <!--3rd-->3248 || <!--4th-->4940 || <!--5th-->6990 || <!--6th-->9220 || <!--7th-->11,500 || <!--8th-->18,770 || <!--9th-->21,400 || <!--10th-->23,960

|-

| 26 || Fe || iron

| <!--1st-->762.5 || <!--2nd-->1561.9 || <!--3rd-->2957 || <!--4th-->5290 || <!--5th-->7240 || <!--6th-->9560 || <!--7th-->12,060 || <!--8th-->14,580 || <!--9th-->22,540 || <!--10th-->25,290

|-

| 27 || Co || cobalt

| <!--1st-->760.4 || <!--2nd-->1648 || <!--3rd-->3232 || <!--4th-->4950 || <!--5th-->7670 || <!--6th-->9840 || <!--7th-->12,440 || <!--8th-->15,230 || <!--9th-->17,959 || <!--10th-->26,570

|-

| 28 || Ni || nickel

| <!--1st-->737.1 || <!--2nd-->1753.0 || <!--3rd-->3395 || <!--4th-->5300 || <!--5th-->7339 || <!--6th-->10,400 || <!--7th-->12,800 || <!--8th-->15,600 || <!--9th-->18,600 || <!--10th-->21,670

|-

| 29 || Cu || copper

| <!--1st-->745.5 || <!--2nd-->1957.9 || <!--3rd-->3555 || <!--4th-->5536 || <!--5th-->7700 || <!--6th-->9900 || <!--7th-->13,400 || <!--8th-->16,000 || <!--9th-->19,200 || <!--10th-->22,400

|-

| 30 || Zn || zinc

| <!--1st-->906.4 || <!--2nd-->1733.3 || <!--3rd-->3833 || <!--4th-->5731 || <!--5th-->7970 || <!--6th-->10,400 || <!--7th-->12,900 || <!--8th-->16,800 || <!--9th-->19,600 || <!--10th-->23,000

|-

| 31 || Ga || gallium

| <!--1st-->578.8 || <!--2nd-->1979.3 || <!--3rd-->2963 || <!--4th-->6180

|-

| 32 || Ge || germanium

| <!--1st-->762 || <!--2nd-->1537.5 || <!--3rd-->3302.1 || <!--4th-->4411 || <!--5th-->9020

|-

| 33 || As || arsenic

| <!--1st-->947.0 || <!--2nd-->1798 || <!--3rd-->2735 || <!--4th-->4837 || <!--5th-->6043 || <!--6th-->12,310

|-

| 34 || Se || selenium

| <!--1st-->941.0 || <!--2nd-->2045 || <!--3rd-->2973.7 || <!--4th-->4144 || <!--5th-->6590 || <!--6th-->7880 || <!--7th-->14,990

|-

| 35 || Br || bromine

| <!--1st-->1139.9 || <!--2nd-->2103 || <!--3rd-->3470 || <!--4th-->4560 || <!--5th-->5760 || <!--6th-->8550 || <!--7th-->9940 || <!--8th-->18,600

|-

| 36 || Kr || krypton

| <!--1st-->1350.8 || <!--2nd-->2350.4 || <!--3rd-->3565 || <!--4th-->5070 || <!--5th-->6240 || <!--6th-->7570 || <!--7th-->10,710 || <!--8th-->12,138 || <!--9th-->22,274 || <!--10th-->25,880

|-

| 37 || Rb || rubidium

| <!--1st-->403.0 || <!--2nd-->2633 || <!--3rd-->3860 || <!--4th-->5080 || <!--5th-->6850 || <!--6th-->8140 || <!--7th-->9570 || <!--8th-->13,120 || <!--9th-->14,500 || <!--10th-->26,740

|-

| 38 || Sr || strontium

| <!--1st-->549.5 || <!--2nd-->1064.2 || <!--3rd-->4138 || <!--4th-->5500 || <!--5th-->6910 || <!--6th-->8760 || <!--7th-->10,230 || <!--8th-->11,800 || <!--9th-->15,600 || <!--10th-->17,100

|-

| 39 || Y || yttrium

| <!--1st-->600 || <!--2nd-->1180 || <!--3rd-->1980 || <!--4th-->5847 || <!--5th-->7430 || <!--6th-->8970 || <!--7th-->11,190 || <!--8th-->12,450 || <!--9th-->14,110 || <!--10th-->18,400

|-

| 40 || Zr || zirconium

| <!--1st-->640.1 || <!--2nd-->1270 || <!--3rd-->2218 || <!--4th-->3313 || <!--5th-->7752 || <!--6th-->9500

|-

| 41 || Nb || niobium

| <!--1st-->652.1 || <!--2nd-->1380 || <!--3rd-->2416 || <!--4th-->3700 || <!--5th-->4877 || <!--6th-->9847 || <!--7th-->12,100

|-

| 42 || Mo || molybdenum

| <!--1st-->684.3 || <!--2nd-->1560 || <!--3rd-->2618 || <!--4th-->4480 || <!--5th-->5257 || <!--6th-->6640.8 || <!--7th-->12,125 || <!--8th-->13,860 || <!--9th-->15,835 || <!--10th-->17,980

|-

| 43 || Tc || technetium

| <!--1st-->686.9 || <!--2nd-->1470 || <!--3rd-->2850

|-

| 44 || Ru || ruthenium

| <!--1st-->710.2 || <!--2nd-->1620 || <!--3rd-->2747

|-

| 45 || Rh || rhodium

| <!--1st-->719.7 || <!--2nd-->1740 || <!--3rd-->2997

|-

| 46 || Pd || palladium

| <!--1st-->804.4 || <!--2nd-->1870 || <!--3rd-->3177

|-

| 47 || Ag || silver

| <!--1st-->731.0 || <!--2nd-->2070 || <!--3rd-->3361

|-

| 48 || Cd || cadmium

| <!--1st-->867.8 || <!--2nd-->1631.4 || <!--3rd-->3616

|-

| 49 || In || indium

| <!--1st-->558.3 || <!--2nd-->1820.7 || <!--3rd-->2704 || <!--4th-->5210

|-

| 50 || Sn || tin

| <!--1st-->708.6 || <!--2nd-->1411.8 || <!--3rd-->2943.0 || <!--4th-->3930.3 || <!--5th-->7456

|-

| 51 || Sb || antimony

| <!--1st-->834 || <!--2nd-->1594.9 || <!--3rd-->2440 || <!--4th-->4260 || <!--5th-->5400 || <!--6th-->10,400

|-

| 52 || Te || tellurium

| <!--1st-->869.3 || <!--2nd-->1790 || <!--3rd-->2698 || <!--4th-->3610 || <!--5th-->5668 || <!--6th-->6820 || <!--7th-->13,200

|-

| 53 || I || iodine

| <!--1st-->1008.4 || <!--2nd-->1845.9 || <!--3rd-->3180

|-

| 54 || Xe || xenon

| <!--1st-->1170.4 || <!--2nd-->2046.4 || <!--3rd-->3099.4

|-

| 55 || Cs || caesium

| <!--1st-->375.7 || <!--2nd-->2234.3 || <!--3rd-->3400

|-

| 56 || Ba || barium

| <!--1st-->502.9 || <!--2nd-->965.2 || <!--3rd-->3600

|-

| 57 || La || lanthanum

| <!--1st-->538.1 || <!--2nd-->1067 || <!--3rd-->1850.3 || <!--4th-->4819 || <!--5th-->5940

|-

| 58 || Ce || cerium

| <!--1st-->534.4 || <!--2nd-->1050 || <!--3rd-->1949 || <!--4th-->3547 || <!--5th-->6325 || <!--6th-->7490

|-

| 59 || Pr || praseodymium

| <!--1st-->527 || <!--2nd-->1020 || <!--3rd-->2086 || <!--4th-->3761 || <!--5th-->5551

|-

| 60 || Nd || neodymium

| <!--1st-->533.1 || <!--2nd-->1040 || <!--3rd-->2130 || <!--4th-->3900

|-

| 61 || Pm || promethium

| <!--1st-->540 || <!--2nd-->1050 || <!--3rd-->2150 || <!--4th-->3970

|-

| 62 || Sm || samarium

| <!--1st-->544.5 || <!--2nd-->1070 || <!--3rd-->2260 || <!--4th-->3990

|-

| 63 || Eu || europium

| <!--1st-->547.1 || <!--2nd-->1085 || <!--3rd-->2404 || <!--4th-->4120

|-

| 64 || Gd || gadolinium

| <!--1st-->593.4 || <!--2nd-->1170 || <!--3rd-->1990 || <!--4th-->4250

|-

| 65 || Tb || terbium

| <!--1st-->565.8 || <!--2nd-->1110 || <!--3rd-->2114 || <!--4th-->3839

|-

| 66 || Dy || dysprosium

| <!--1st-->573.0 || <!--2nd-->1130 || <!--3rd-->2200 || <!--4th-->3990

|-

| 67 || Ho || holmium

| <!--1st-->581.0 || <!--2nd-->1140 || <!--3rd-->2204 || <!--4th-->4100

|-

| 68 || Er || erbium

| <!--1st-->589.3 || <!--2nd-->1150 || <!--3rd-->2194 || <!--4th-->4120

|-

| 69 || Tm || thulium

| <!--1st-->596.7 || <!--2nd-->1160 || <!--3rd-->2285 || <!--4th-->4120

|-

| 70 || Yb || ytterbium

| <!--1st-->603.4 || <!--2nd-->1174.8 || <!--3rd-->2417 || <!--4th-->4203

|-

| 71 || Lu || lutetium

| <!--1st-->523.5 || <!--2nd-->1340 || <!--3rd-->2022.3 || <!--4th-->4370 || <!--5th-->6445

|-

| 72 || Hf || hafnium

| <!--1st-->658.5 || <!--2nd-->1440 || <!--3rd-->2250 || <!--4th-->3216

|-

| 73 || Ta || tantalum

| <!--1st-->761 || <!--2nd-->1500

|-

| 74 || W || tungsten

| <!--1st-->770 || <!--2nd-->1700

|-

| 75 || Re || rhenium

| <!--1st-->760 || <!--2nd-->1260 || <!--3rd-->2510 || <!--4th-->3640

|-

| 76 || Os || osmium

| <!--1st-->840 || <!--2nd-->1600

|-

| 77 || Ir || iridium

| <!--1st-->880 || <!--2nd-->1600

|-

| 78 || Pt || platinum

| <!--1st-->870 || <!--2nd-->1791

|-

| 79 || Au || gold

| <!--1st-->890.1 || <!--2nd-->1980

|-

| 80 || Hg || mercury

| <!--1st-->1007.1 || <!--2nd-->1810 || <!--3rd-->3300

|-

| 81 || Tl || thallium

| <!--1st-->589.4 || <!--2nd-->1971 || <!--3rd-->2878

|-

| 82 || Pb || lead

| <!--1st-->715.6 || <!--2nd-->1450.5 || <!--3rd-->3081.5 || <!--4th-->4083 || <!--5th-->6640

|-

| 83 || Bi || bismuth

| <!--1st-->703 || <!--2nd-->1610 || <!--3rd-->2466 || <!--4th-->4370 || <!--5th-->5400 || <!--6th-->8520

|-

| 84 || Po || polonium

| <!--1st-->812.1

|-

| 85 || At || astatine

| <!--1st-->899.003

|-

| 86 || Rn || radon

| <!--1st-->1037

|-

| 87 || Fr || francium

| <!--1st-->393

|-

| 88 || Ra || radium

| <!--1st-->509.3 || <!--2nd-->979.0

|-

| 89 || Ac || actinium

| <!--1st-->499 || <!--2nd-->1170||<!--3rd-->1900||<!--4th-->4700

|-

| 90 || Th || thorium

| <!--1st-->587 || <!--2nd-->1110 || <!--3rd-->1978 || <!--4th-->2780

|-

| 91 || Pa || protactinium

| <!--1st-->568||<!--2nd-->1128|| <!--3rd-->1814 ||<!--4th-->2991

|-

| 92 || U || uranium

| <!--1st-->597.6 || <!--2nd-->1420|| <!--3rd-->1900 ||<!--4th-->3145

|-

| 93 || Np || neptunium

| <!--1st-->604.5|| <!--2nd-->1128|| <!--3rd-->1997 ||<!--4th-->3242

|-

| 94 || Pu || plutonium

| <!--1st-->584.7|| <!--2nd-->1128|| <!--3rd-->2084 ||<!--4th-->3338

|-

| 95 || Am || americium

| <!--1st-->578|| <!--2nd-->1158|| <!--3rd-->2132 ||<!--4th-->3493

|-

| 96 || Cm || curium

| <!--1st-->581|| <!--2nd-->1196|| <!--3rd-->2026 ||<!--4th-->3550

|-

| 97 || Bk || berkelium

| <!--1st-->601|| <!--2nd-->1186|| <!--3rd-->2152 ||<!--4th-->3434

|-

| 98 || Cf || californium

| <!--1st-->608|| <!--2nd-->1206|| <!--3rd-->2267 ||<!--4th-->3599

|-

| 99 || Es || einsteinium

| <!--1st-->619|| <!--2nd-->1216|| <!--3rd-->2334 ||<!--4th-->3734

|-

| 100 || Fm || fermium

| <!--1st-->629|| <!--2nd-->1225|| <!--3rd-->2363 ||<!--4th-->3792

|-

| 101 || Md || mendelevium

| <!--1st-->636|| <!--2nd-->1235|| <!--3rd-->2470 ||<!--4th-->3840

|-

| 102 || No || nobelium

| <!--1st-->639|| <!--2nd-->1254|| <!--3rd-->2643 ||<!--4th-->3956

|-

| 103 || Lr || lawrencium

| <!--1st-->479|| <!--2nd-->1428|| <!--3rd-->2228 ||<!--4th-->4910

|-

| 104 || Rf || rutherfordium

| <!--1st-->580 || <!--2nd-->1390 || <!--3rd-->2300 || <!--4th-->3080

|-

| 105 || Db || dubnium

| <!--1st-->665 || <!--2nd-->1547 || <!--3rd-->2378 || <!--4th-->3299 || <!--5th-->4305

|-

| 106 || Sg || seaborgium

| <!--1st-->757 || <!--2nd-->1733 || <!--3rd-->2484 || <!--4th-->3416 || <!--5th-->4562 || <!--6th-->5716

|-

| 107 || Bh || bohrium

| <!--1st-->740 || <!--2nd-->1690 || <!--3rd-->2570 || <!--4th-->3600 || <!--5th-->4730 || <!--6th-->5990 || <!--7th-->7230

|-

| 108 || Hs || hassium

| <!--1st-->730 || <!--2nd-->1760 || <!--3rd-->2830 || <!--4th-->3640 || <!--5th-->4940 || <!--6th-->6180 || <!--7th-->7540 || <!--8th-->8860

|-

| 109 || Mt || meitnerium

| <!--1st-->800 || <!--2nd-->1820 || <!--3rd-->2900 || <!--4th-->3900 || <!--5th-->4900

|-

| 110 || Ds || darmstadtium

| <!--1st-->960 || <!--2nd-->1890 || <!--3rd-->3030 || <!--4th-->4000 || <!--5th-->5100

|-

| 111 || Rg || roentgenium

| <!--1st-->1020 || <!--2nd-->2070 || <!--3rd-->3080 || <!--4th-->4100 || <!--5th-->5300

|-

| 112 || Cn || copernicium

| <!--1st-->1155 || <!--2nd-->2170 || <!--3rd-->3160 || <!--4th-->4200 || <!--5th-->5500

|-

| 113 || Nh || nihonium

| <!--1st-->707.2 || <!--2nd-->2309 || <!--3rd-->3020 || <!--4th-->4382 || <!--5th-->5638

|-

| 114 || Fl || flerovium

| <!--1st-->832.2 || <!--2nd-->1600 || <!--3rd-->3370 || <!--4th-->4400 || <!--5th-->5850

|-

| 115 || Mc || moscovium

| <!--1st-->538.3 || <!--2nd-->1760 || <!--3rd-->2650 || <!--4th-->4680 || <!--5th-->5720

|-

| 116 || Lv || livermorium

| <!--1st-->663.9 || <!--2nd-->1330 || <!--3rd-->2850 || <!--4th-->3810 || <!--5th-->6080

|-

| 117 || Ts || tennessine

| <!--1st-->736.9 || <!--2nd-->1435.4 || <!--3rd-->2161.9 || <!--4th-->4012.9 || <!--5th-->5076.4

|-

| 118 || Og || oganesson

| <!--1st-->860.1 || <!--2nd-->1560

|-

| 119 || Uue || ununennium

| <!--1st-->463.1 || <!--2nd-->1700

|-

| 120 || Ubn || unbinilium

| <!--1st-->563.3 || <!--2nd-->

|-

| 121 || Ubu || unbiunium

| <!--1st-->429.4 || <!--2nd--> 1110 || <!--3rd--> 1710 || <!--4th--> 4270

|-

| 122 || Ubb || unbibium

| <!--1st-->545 || <!--2nd--> 1090 || <!--3rd--> 1848 || <!--4th--> 2520

|}

11th&ndash;20th ionization energies

{| class="wikitable sortable" style="font-size:90%;"

! number !! symbol !! name

! 11th !! 12th !! 13th !! 14th !! 15th !! 16th !! 17th !! 18th !! 19th !! 20th

|-

| 11 || Na || sodium

| <!--11th-->159,076

|-

| 12 || Mg || magnesium

| <!--11th-->169,988 || <!--12th-->189,368

|-

| 13 || Al || aluminium

| <!--11th-->42,647 || <!--12th-->201,266|| <!--13th-->222,316

|-

| 14 || Si || silicon

| <!--11th-->45,962 || <!--12th-->50,502 || <!--13th-->235,196 || <!--14th-->257,923

|-

| 15 || P || phosphorus

| <!--11th-->46,261 || <!--12th-->54,110 || <!--13th-->59,024 || <!--14th-->271,791 || <!--15th-->296,195

|-

| 16 || S || sulfur

| <!--11th-->48,710 || <!--12th-->54,460 || <!--13th-->62,930 || <!--14th-->68,216 || <!--15th-->311,048 || <!--16th-->337,138

|-

| 17 || Cl || chlorine

| <!--11th-->51,068 || <!--12th-->57,119 || <!--13th-->63,363 || <!--14th-->72,341 || <!--15th-->78,095 || <!--16th-->352,994 || <!--17th-->380,760

|-

| 18 || Ar || argon

| <!--11th-->52,002 || <!--12th-->59,653 || <!--13th-->66,199 || <!--14th-->72,918 || <!--15th-->82,473 || <!--16th-->88,576 || <!--17th-->397,605 || <!--18th-->427,066

|-

| 19 || K || potassium

| <!--11th-->54,490 || <!--12th-->60,730 || <!--13th-->68,950 || <!--14th-->75,900 || <!--15th-->83,080 || <!--16th-->93,400 || <!--17th-->99,710 || <!--18th-->444,880 || <!--19th-->476,063

|-

| 20 || Ca || calcium

| <!--11th-->57,110 || <!--12th-->63,410 || <!--13th-->70,110 || <!--14th-->78,890 || <!--15th-->86,310 || <!--16th-->94,000 || <!--17th-->104,900 || <!--18th-->111,711 || <!--19th-->494,850 || <!--20th-->527,762

|-

| 21 || Sc || scandium

| <!--11th-->24,102 || <!--12th-->66,320 || <!--13th-->73,010 || <!--14th-->80,160 || <!--15th-->89,490 || <!--16th-->97,400 || <!--17th-->105,600 || <!--18th-->117,000 || <!--19th-->124,270 || <!--20th-->547,530

|-

| 22 || Ti || titanium

| <!--11th-->25,575 || <!--12th-->28,125 || <!--13th-->76,015 || <!--14th-->83,280 || <!--15th-->90,880 || <!--16th-->100,700 || <!--17th-->109,100 || <!--18th-->117,800 || <!--19th-->129,900 || <!--20th-->137,530

|-

| 23 || V || vanadium

| <!--11th-->24,670 || <!--12th-->29,730 || <!--13th-->32,446 || <!--14th-->86,450 || <!--15th-->94,170 || <!--16th-->102,300 || <!--17th-->112,700 || <!--18th-->121,600 || <!--19th-->130,700 || <!--20th-->143,400

|-

| 24 || Cr || chromium

| <!--11th-->26,130 || <!--12th-->28,750 || <!--13th-->34,230 || <!--14th-->37,066 || <!--15th-->97,510 || <!--16th-->105,800 || <!--17th-->114,300 || <!--18th-->125,300 || <!--19th-->134,700 || <!--20th-->144,300

|-

| 25 || Mn || manganese

| <!--11th-->27,590 || <!--12th-->30,330 || <!--13th-->33,150 || <!--14th-->38,880 || <!--15th-->41,987 || <!--16th-->109,480 || <!--17th-->118,100 || <!--18th-->127,100 || <!--19th-->138,600 || <!--20th-->148,500

|-

| 26 || Fe || iron

| <!--11th-->28,000 || <!--12th-->31,920 || <!--13th-->34,830 || <!--14th-->37,840 || <!--15th-->44,100 || <!--16th-->47,206 || <!--17th-->122,200 || <!--18th-->131,000 || <!--19th-->140,500 || <!--20th-->152,600

|-

| 27 || Co || cobalt

| <!--11th-->29,400 || <!--12th-->32,400 || <!--13th-->36,600 || <!--14th-->39,700 || <!--15th-->42,800 || <!--16th-->49,396 || <!--17th-->52,737 || <!--18th-->134,810 || <!--19th-->145,170 || <!--20th-->154,700

|-

| 28 || Ni || nickel

| <!--11th-->30,970 || <!--12th-->34,000 || <!--13th-->37,100 || <!--14th-->41,500 || <!--15th-->44,800 || <!--16th-->48,100 || <!--17th-->55,101 || <!--18th-->58,570 || <!--19th-->148,700 || <!--20th-->159,000

|-

| 29 || Cu || copper

| <!--11th-->25,600 || <!--12th-->35,600 || <!--13th-->38,700 || <!--14th-->42,000 || <!--15th-->46,700 || <!--16th-->50,200 || <!--17th-->53,700 || <!--18th-->61,100 || <!--19th-->64,702 || <!--20th-->163,700

|-

| 30 || Zn || zinc

| <!--11th-->26,400 || <!--12th-->29,990 || <!--13th-->40,490 || <!--14th-->43,800 || <!--15th-->47,300 || <!--16th-->52,300 || <!--17th-->55,900 || <!--18th-->59,700 || <!--19th-->67,300 || <!--20th-->71,200

|-

| 36 || Kr || krypton

| <!--11th-->29,700 || <!--12th-->33,800 || <!--13th-->37,700 || <!--14th-->43,100 || <!--15th-->47,500 || <!--16th-->52,200 || <!--17th-->57,100 || <!--18th-->61,800 || <!--19th-->75,800 || <!--20th-->80,400

|-

| 38 || Sr || strontium

| <!--11th-->31,270

|-

| 39 || Y || yttrium

| <!--11th-->19,900 || <!--12th-->36,090

|-

| 42 || Mo || molybdenum

| <!--11th-->20,190 || <!--12th-->22,219 || <!--13th-->26,930 || <!--14th-->29,196 || <!--15th-->52,490 || <!--16th-->55,000 || <!--17th-->61,400 || <!--18th-->67,700 || <!--19th-->74,000 || <!--20th-->80,400

|}

21st&ndash;30th ionization energies

{| class="wikitable sortable" style="font-size:90%;"

! number !! symbol !! name

! 21st !! 22nd !! 23rd !! 24th !! 25th !! 26th !! 27th !! 28th !! 29th !! 30th

|-

| 21 || Sc || scandium

| <!--21st-->582,163

|-

| 22 || Ti || titanium

| <!--21st-->602,930 || <!--22nd-->639,294

|-

| 23 || V || vanadium

| <!--21st-->151,440 || <!--22nd-->661,050 || <!--23rd-->699,144

|-

| 24 || Cr || chromium

| <!--21st-->157,700 || <!--22nd-->166,090 || <!--23rd-->721,870 || <!--24th-->761,733

|-

| 25 || Mn || manganese

| <!--21st-->158,600 || <!--22nd-->172,500 || <!--23rd-->181,380 || <!--24th-->785,450 || <!--25th-->827,067

|-

| 26 || Fe || iron

| <!--21st-->163,000 || <!--22nd-->173,600 || <!--23rd-->188,100 || <!--24th-->195,200 || <!--25th-->851,800 || <!--26th-->895,161

|-

| 27 || Co || cobalt

| <!--21st-->167,400 || <!--22nd-->178,100 || <!--23rd-->189,300 || <!--24th-->204,500 || <!--25th-->214,100 || <!--26th-->920,870 || <!--27th-->966,023

|-

| 28 || Ni || nickel

| <!--21st-->169,400 || <!--22nd-->182,700 || <!--23rd-->194,000 || <!--24th-->205,600 || <!--25th-->221,400 || <!--26th-->231,490 || <!--27th-->992,718 || <!--28th-->1,039,668

|-

| 29 || Cu || copper

| <!--21st-->174,100 || <!--22nd-->184,900 || <!--23rd-->198,800 || <!--24th-->210,500 || <!--25th-->222,700 || <!--26th-->239,100 || <!--27th-->249,660 || <!--28th-->1,067,358 || <!--29th-->1,116,105

|-

| 30 || Zn || zinc

| <!--21st-->179,100

|-

| 36 || Kr || krypton

| <!--21st-->85,300 || <!--22nd-->90,400 || <!--23rd-->96,300 || <!--24th-->101,400 || <!--25th-->111,100 || <!--26th-->116,290 || <!--27th-->282,500 || <!--28th-->296,200 || <!--29th-->311,400 || <!--30th-->326,200

|-

| 42 || Mo || molybdenum

| <!--21st-->87,000 || <!--22nd-->93,400 || <!--23rd-->98,420 || <!--24th-->104,400 || <!--25th-->121,900 || <!--26th-->127,700 || <!--27th-->133,800 || <!--28th-->139,800 || <!--29th-->148,100 || <!--30th-->154,500

|}

References

• (for predictions)
• (for predictions)