ChemData Symbol Old Group # New Group # Name atomic # atomic mass Notes mp bp density g/mL Electronegativity First Ion. Energy kJ/mol Covalent Atomic Radius pm C C H Ia 1 hydrogen 1 1.01 -259.1 -252.9 6.99E-05 2.1 1312 37 He VIIIa 18 helium 2 4.00 -272.2 -268.9 1.79E-04 2377 32 Li Ia 1 lithium 3 6.94 180.5 1342 5.43E-01 1 520 134 Be IIa 2 beryllium 4 9.01 1278 2970 1.85E+00 1.5 899 90 B IIIa 13 boron 5 10.81 sublimes 2079 2550 2.34E+00 2 801 82 C IVa 14 carbon 6 12.01 graphite 3367 4827 2.25E+00 2.5 1086 77 N Va 15 nitrogen 7 14.01 -209.9 -195.8 1.25E-03 3 1420 75 O VIa 16 oxygen 8 15.99 -218.4 -183 1.43E-03 3.5 1314 73 F VIIa 17 fluorine 9 18.99 -219.8 -188.1 1.70E-03 4 1681 72 Ne VIIIa 18 neon 10 20.18 -248 -248.7 9.00E-04 2088 71 Na Ia 1 sodium 11 22.99 97.8 883 9.71E-01 0.9 495 154 Mg IIa 2 magnesium 12 24.31 649 1090 1.74E+00 1.2 735 130 Al IIIa 13 aluminum 13 26.98 660 2467 2.70E+00 1.5 580 118 Si IVa 14 silicon 14 28.09 1410 2355 2.33E+00 1.8 780 111 P Va 15 phosphorus 15 30.97 white 44.1 280 1.82E+00 2.1 1060 106 S VIa 16 sulfur 16 32.07 yellow 112.8 444.7 2.07E+00 2.5 1005 102 Cl VIIa 17 chlorine 17 35.45 -101 -34.6 3.21E-03 3 1255 99 Ar VIIIa 18 argon 18 39.95 -189.2 -185.7 1.78E-03 1527 97 K Ia 1 potassium 19 39.1 63.25 760 8.60E-01 0.8 419 196 Ca IIa 2 calcium 20 40.08 839 1484 1.55E+00 1 590 174 Sc IIIb 3 scandium 21 44.96 1541 2832 2.99E+00 1.3 633 144 Ti IVb 4 titanium 22 47.88 1660 3287 4.54E+00 1.5 659 136 V Vb 5 vanadium 23 50.94 1890 3380 6.11E+00 1.6 651 125 Cr VIb 6 chromium 24 51.99 1857 2672 7.19E+00 1.6 653 127 Mn VIIb 7 manganese 25 54.94 1244 1962 7.43E+00 1.5 717 139 Fe VIIIb 8 iron 26 55.85 1535 2750 7.86E+00 1.8 763 125 Co VIIIb 9 cobalt 27 58.93 1495 2870 8.90E+00 1.8 761 126 Ni VIIIb 10 nickel 28 58.69 1453 2730 8.90E+00 1.8 737 121 Cu Ib 11 copper 29 63.55 1083 2567 8.96E+00 1.8 746 138 Zn IIb 12 zinc 30 65.38 419.6 906 7.13E+00 1.6 906 131 Ga IIIa 13 gallium 31 69.72 29.8 2403 5.90E+00 1.6 579 126 Ge IVa 14 germanium 32 72.59 947.4 2830 5.32E+00 1.8 762 122 As Va 15 arsenic 33 74.92 (28 atm) sublimes 817 617 5.73E+00 2 947 119 Se VIa 16 selenium 34 78.96 217 685 4.79E+00 2.4 941 116 Br VIIa 17 bromine 35 79.9 -7.2 58.8 3.12E+00 2.8 1140 114 Kr VIIIa 18 krypton 36 83.8 -157 -152 3.74E-03 1356 110 Rb Ia 1 rubidium 37 85.47 38.9 686 1.53E+00 0.8 409 211 Sr IIa 2 strontium 38 87.62 769 1384 2.54E+00 1 550 192 Y IIIb 3 yttrium 39 88.91 1523 3337 4.47E+00 1.3 600 162 Zr IVb 4 zirconium 40 91.22 1852 4377 6.51E+00 1.4 640 148 Nb VIb 5 niobium 41 92.91 2468 4742 8.57E+00 1.6 652 137 Mo VIb 6 molybdenum 42 95.94 2617 4612 1.02E+01 1.8 684 145 Tc VIIb 7 technetium 43 98.00 2172 4877 1.15E+01 1.9 702 156 Ru VIIIb 8 ruthenium 44 101.07 2310 3900 1.24E+01 2.2 710 126 Rh VIIIb 9 rhodium 45 102.91 1966 3727 1.24E+01 2.2 720 135 Pd VIIIb 10 palladium 46 106.40 1554 3140 1.20E+01 2.2 804 131 Ag Ib 11 silver 47 107.87 962 2212 1.05E+01 1.9 731 153 Cd IIb 12 cadmium 48 112.41 320.9 765 8.65E+00 1.7 868 148 In IIIa 13 indium 49 114.82 156.6 2080 7.31E+00 1.7 558 144 Sn IVa 14 tin 50 118.69 232 2270 7.31E+00 1.8 709 141 Sb Va 15 antimony 51 121.75 631 1950 6.69E+00 1.9 834 138 Te VIa 16 tellurium 52 127.60 449.5 989.8 6.24E+00 2.1 869 135 I VIIa 17 iodine 53 126.90 113.5 184 4.93E+00 2.5 1008 133 Xe VIIIa 18 xenon 54 131.30 -111.8 -107.1 5.89E-03 1176 131 Cs Ia 1 cesium 55 132.91 28.4 669 1.87E+00 0.7 382 225 Ba IIa 2 barium 56 137.33 725 1640 3.50E+00 0.9 508 198 La IIIb 3 lanthanum 57 138.91 920 3454 6.15E+00 1.1 538 169 Ce f cerium 58 140.12 798 3257 6.66E+00 1.1 534 Pr f praseodymium 59 140.91 931 3017 6.77E+00 1.1 527 Nd f neodymium 60 144.24 1016 3127 7.00E+00 1.2 533 Pm f promethium 61 145.00 1042 3000 7.26E+00 540 Sm f samarium 62 150.40 1074 1794 7.52E+00 1.2 545 Eu f europium 63 151.96 822 1529 5.24E+00 547 Gd f gadolinium 64 157.25 1313 3273 7.90E+00 1.1 593 Tb f terbium 65 158.93 1365 3230 8.23E+00 1.2 566 Dy f dysprosium 66 162.50 1412 2567 8.55E+00 573 Ho f holmium 67 164.93 1474 2700 8.80E+00 1.2 581 Er f erbium 68 167.26 1529 2868 9.07E+00 1.2 589 Tm f thulium 69 168.93 1545 1950 9.32E+00 1.2 597 Yb f ytterbium 70 173.04 819 1196 6.97E+00 1.1 603 Lu f lutetium 71 174.97 1663 3402 9.84E+00 1.2 524 Hf IVb 4 hafnium 72 178.49 2227 4600 1.33E+01 1.3 659 Ta Vb 5 tantalum 73 180.95 2996 5425 1.66E+01 1.5 761 W VIb 6 tungsten 74 183.85 3410 5660 1.93E+01 1.7 770 Re VIIb 7 rhenium 75 186.21 3180 5600 2.10E+01 1.9 760 Os VIIIb 8 osmium 76 190.20 3045 5030 2.26E+01 2.2 840 Ir VIIIb 9 iridium 77 192.22 2410 4130 2.24E+01 2.2 880 Pt VIIIb 10 platinum 78 195.09 1772 3827 2.14E+01 2.2 870 Au Ib 11 gold 79 196.97 1064 3080 1.93E+01 2.4 890 Hg IIb 12 mercury 80 200.59 -38.9 357 1.35E+01 1.9 1007 Tl IIIa 13 thallium 81 204.37 303 1457 1.19E+01 1.8 589 171 Pb IVa 14 lead 82 207.20 327.5 1740 1.14E+01 1.8 723 175 Bi Va 15 bismuth 83 208.98 271 1560 9.75E+00 1.9 711 170 Po VIa 16 polonium 84 209.00 254 962 9.32E+00 2 821 176 At VIIa 17 astatine 85 210.00 302 337 2.2 920 142 Rn VIIIa 18 radon 86 222.00 -71 -61.8 9.73E-03 1042 140 Fr Ia 1 francium 87 223.02 27 677 0.7 380 Ra IIa 2 radium 88 226.03 700 1140 5.00E+00 0.9 509 Ac IIIb 3 actinium 89 227.03 1050 3200 1.01E+01 1.1 499 Th f thorium 90 232.04 1750 4790 1.17E+01 1.3 587 Pa f protactinium 91 231.04 1570 4000 1.54E+01 1.5 568 U f uranium 92 238.03 1132 3818 1.90E+01 1.7 598 Np f neptunium 93 237.05 640 3900 2.02E+01 1.3 605 Pu f plutonium 94 244 641 3232 1.98E+01 1.3 585 Am f americium 95 243 994 2607 1.37E+01 1.3 578 Cm f curium 96 247 1340 1.35E+01 581 Bk f berkelium 97 247 986 1.40E+01 601 Cf f californium 98 251 608 Es f einsteinium 99 252 619 Fm f fermium 100 257 627 Md f mendelevium 101 258 635 No f nobelium 102 259 642 Lr f lawrencium 103 260 Rf IVb 4 Rutherfordium 104 261 Ha Vb 5 Hahnium 105 262 Sg VIb 6 Seaborgium 106 263 Uns VIIb 7 Unnilseptium 107 262 Uno VIIIb 8 Unniloctium 108 265 Une VIIIb 9 Unnilennium 109 266