週期 4

19 K 鉀 39.098 20 Ca 鈣 40.08 21 Sc 鈧 44.956 22 Ti 鈦 47.867 23 V 釩 50.941 24 Cr 鉻 51.996 25 Mn 錳 54.938 26 Fe 鐵 55.84 27 Co 鈷 58.933 28 Ni 鎳 58.693 29 Cu 銅 63.55 30 Zn 鋅 65.4 31 Ga 鎵 69.723 32 Ge 鍺 72.63 33 As 砷 74.922 34 Se 硒 78.97 35 Br 溴 79.9 36 Kr 氪 83.8