Trends Periods Groups Electron configuration Atomic radii Ionization energy Electronegativity Electron affinity Metallic character Alkali metals 1 Hydrogen H 3 Lithium Li 11 Sodium Na 19 Pota**ium K 37 Rubidium Rb 55 Caesium Cs 87 Francium Fr Alkali earth metals 4 Beryllium Be 12 Magnesium Mg 20 Calcium Ca 38 Strontium Sr 56 Barium Ba 88 Radium Ra Transition metal 21 Scandium Sc 22 Titanium Ti 23 Vanadium V 24 Chromium Cr 25 Manganese Mn 26 Iron Fe 27 Cobalt Co 28 Nickel Ni 29 Copper Cu 30 Zinc Zn 39 Yttrium Y 40 Zirconium Zr 41 Niobium Nb 42 Molybdenum Mo 43 Technetium Tc 44 Ruthenium Ru 45 Rhodium Rh 46 Palladium Pd 47 Silver Ag 48 Cadmium Cd 72 Hafnium Hf 73 Tantalum Ta 74 Tungsten W 75 Rhenium Re 76 Osmium Os 77 Iridium Ir 78 Platinum Pt 79 Gold Au 80 Mercury Hg 104 Rutherfordium Rf 105 Dubnium Db 106 Seaborgium Sg 107 Bohrium Bh 108 Ha**ium Hs 112 Copernicium Cn Poor metals 13 Aluminium Al 31 Gallium Ga 49 Indium In 50 Tin Sn 81 Thallium Tl 82 Lead Pb 83 Bismuth Bi 84 Polonium Po Metalloids 5 Boron B 14 Silicon Si 32 Germanium Ge 33 Arsenic As 51 Antimony Sb 52 Tellurium Te 85 Astatine At Polyatomic nonmetal 6 Carbon C 15 Phosphorus P 16 Sulfur S 34 Selenium Se Diatomic nonmetal 7 Nitrogen N 8 Oxygen O 9 Fluorine F 17 Chlorine Cl 35 Bromine Br 53 Iodine I Noble gas 2 Helium He 10 Neon Ne 18 Argon Ar 36 Krypton Kr 54 Xenon Xe 86 Radon Rn Lanthanides 57 Lanthanum La 58 Cerium Ce 59 Praseodymium Pr 60 Neodymium Nd 61 Promethium Pm 62 Samarium Sm 63 Europium Eu 64 Gadolinium Gd 65 Terbium Tb 66 Dysprosium Dy 67 Holmium Ho 68 Erbium Er 69 Thulium Tm 70 Ytterbium Yb 71 Lutetium Lu Actinides 89 Actinium Ac 90 Thorium Th 91 Protactinium Pa 92 Uranium U 93 Neptunium Np 94 Plutonium Pu 95 Americium Am 96 Curium Cm 97 Berkelium Bk 98 Californium Cf 99 Einsteinium Es 100 Fermium Fm 101 Mendelevium Md 102 Nobelium No 103 Lawrencium Lr Unknown 109 Meitnerium Mt 110 Darmstadtium Ds 111 Roentgenium Rg 113 Ununtrium Uut 114 Flerovium Uuq 115 Ununpentium Uup 116 Livermorium Lv 117 Ununseptium Uus 118 Ununoctium Uuo